Category: Class 12 Biology Objective Questions

250+ TOP MCQs on Plant Breeding for Disease Resistance and Answers

Biology Multiple Choice Questions on “Plant Breeding for Disease Resistance”.

1. Which of the following is not responsible for crop losses?
a) Fungi
b) Bacteria
c) Virus
d) Earthworm
Answer: d
Clarification: A wide range of fungal, bacterial and viral pathogens, affect the yield of cultivated crop species, especially in tropical climates. Crop losses can often be significant, up to 20-30 per cent, or sometimes even total.

2. Which of the following term is used for organisms which are attacked by pathogens?
a) Crop
b) Variety
c) Host
d) Susceptible host
Answer: d
Clarification: The term susceptible host is used for those organisms which are not resistant to the pathogens but are attacked and harmed by pathogens. The susceptible individuals in which a disease is caused by a pathogen is called as host.

3. How is the resistance of the host plant towards a pathogen determined?
a) By looking at the leaves
b) By researching the seed
c) By studying the genetic constitution of the plant
d) By cutting the stem
Answer: c
Clarification: Resistance of the host plant is the ability to prevent the pathogen from causing disease and is determined by the genetic constitution of the host plant. Before breeding is undertaken, it is important to know about the causative organism and the mode of transmission.

4. How does the development of disease-resistant plants enhance food production?
a) Reduce the dependence on fertilizers
b) Reduce the dependence of fungicides
c) Reduce the dependence of water
d) Reduce the dependence of air
Answer: b
Clarification: When there are crop losses, then breeding and development of cultivars resistant to disease enhance food production. This also helps reduce the dependence on the use of fungicides and bacteriocides.

5. Which of the following is not a sequential step of breeding disease resistance crop?
a) Harvesting crops
b) Screening germplasm
c) The hybridisation of selected parents
d) Selection and evaluation of hybrids
Answer: a
Clarification: The various sequential steps of breeding disease resistance crop are screening germplasm for resistance sources, hybridisation of selected parents, selection and evaluation of the hybrids and testing and release of new varieties.

6. Which of the following is a variety of wheat crop?
a) Pusa Swarnim
b) Pusa Shubhra
c) Himgiri
d) Pusa Komal
Answer: a
Clarification: Himgiri is the variety of Wheat crop. Pusa Swarnim, Pusa Shubhra and Pusa Komal are the varieties of Brassica, Cauliflower and Cowpea respectively.

7. Which of the following crops is resistant to the chilly mosaic virus?
a) Cowpea
b) Cauliflower
c) Chilli
d) Brassica
Answer: c
Clarification: Chilli crop is resistant to chilly mosaic virus, tobacco mosaic virus and leaf curl disease. Cowpea is resistant to bacterial blight. Cauliflower is resistant to black rot and curl blight black rot disease. Brassica is resistant to white rust disease.

8. Availability of a limited number of disease resistance genes constrains conventional breeding practices.
a) True
b) False
Answer: a
Clarification: Conventional breeding is often constrained by the availability of a limited number of disease resistance genes that are present and identified in various crop varieties or wild relatives. Inducing mutations in plants through diverse means and then screening the plant materials for resistance sometimes leads to desirable genes being identified.

9. What is a mutation?
a) Change in DNA
b) Change in the entire genetic makeup of the organism
c) Change in RNA
d) Change in base sequence within genes
Answer: d
Clarification: Mutation is the process by which genetic variations are created through changes in the base sequence within genes resulting in the creation of a new character or trait not found in the parental type.

10. Which of the following is used to induce mutations in plants?
a) Radiations
b) Water
c) Virus
d) Leaves
Answer: a
Clarification: It is possible to induce mutations artificially in plants through the use of chemicals or radiations (gamma radiations), and selecting and using the plants that have the desired character as a source of breeding. This process is known as mutation breeding.

11. In mung bean, resistance to chilly mosaic virus and powdery mildew were induced by mutations.
a) True
b) False
Answer: b
Clarification: In mung bean, resistance to yellow mosaic virus and powdery mildew were induced by mutations. This process involves the source of resistance genes that are in the same crop species, which has to be bred for disease resistance, or in a related wild species.

12. Resistance to the yellow mosaic virus in bhindi (Abelmoschus esculentus) resulted in a new variety called _________
a) Pusa Sadabahar
b) Parbhani Kranti
c) Himgiri
d) Pusa Shubhra
Answer: b
Clarification: Resistance to the yellow mosaic virus in bhindi (Abelmoschus esculentus) was transferred from a wild species and resulted in a new variety of Abelmoschus esculentus called Parbhani Kranti. Transfer of resistance genes is achieved by sexual hybridisation between the target and the source plant followed by selection.

250+ TOP MCQs on Microbes in Production of Biogas and Answers

Biology Multiple Choice Questions on “Microbes in Production of Biogas”.

1. Which of the following gases is not included in biogas?
a) CH4
b) H2S
c) CO2
d) H2O
Answer: d
Clarification: Certain bacteria produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide. These gases form biogas and can be used as a source of energy as it is inflammable.

2. On which medium do certain bacteria grow to produce biogas?
a) Lignin
b) Cellulose
c) Chitin
d) Cheese
Answer: b
Clarification: Certain bacteria which produce biogas like the methanogens particularly grow anaerobically on cellulosic material to produce large amounts of methane with carbon dioxide and hydrogen.

3. What do we collectively call the biogas producing bacteria?
a) Archaebacteria
b) Cyanobacteria
c) Eubacteria
d) Methanogens
Answer: d
Clarification: The biogas producing bacteria are collectively known as methanogens and one such common bacterium is Methanobacterium. These bacteria are commonly found in the anaerobic sludge during the sewage treatment and also in the rumen of cattle.

4. In rumen of cattle, methanogens help in the breakdown of cellulose.
a) True
b) False
Answer: a
Clarification: A lot of cellulosic material is present in the food of cattle. In the rumen, these bacteria help in the breakdown of cellulose and play an important role in the nutrition of cattle.

5. On which of the following factors does the type of gas produced depend?
a) Substrate
b) Cofactors
c) Catalysts
d) Product
Answer: a
Clarification: The type of gas produced depends upon the microbes and the organic substrates they utilise. For example, in the fermentation of dough, cheese making and production of beverages, the main gas produced is CO2.

6. Which of the following gas is produced using dung of cattle?
a) Greenhouse gas
b) Nitrous gas
c) Gobar gas
d) Water-gas
Answer: c
Clarification: The excreta or dung of the cattle, commonly called gobar is rich in methanogens. Therefore, dung can be used for the generation of biogas, commonly called gobar gas.

7. What is the height of the concrete tank used in biogas plant?
a) 10-15 metres
b) 15-20 metres
c) 10-15 feet
d) 15-20 feet
Answer: c
Clarification: The biogas plant consists of a concrete tank which is 10-15 feet deep and in which bio-wastes are collected and a slurry of dung is fed.

8. Which of the following is not true for a biogas plant?
a) The floating cover is placed over slurry
b) Biogas plant does not have an outlet
c) The slurry is removed and may be used as a fertiliser
d) The concrete tank is 10-15 feet deep
Answer: b
Clarification: The biogas plant has a 10-15 feet deep concrete tank. A floating cover is placed over slurry which keeps on rising as the gas is produced in the tank due to the microbial activity. The biogas plant has an outlet, which is connected to a pipe to supply biogas to nearby houses. Also, the slurry can be removed and may be used as a fertiliser.

9. Biogas plants are more often built in urban areas.
a) True
b) False
Answer: b
Clarification: Cattle dung is available in large quantities in rural areas where cattle are used for a variety of purposes. So biogas plants are more often built in rural areas. The biogas is used for cooking and lighting.

10. What is the full form of IARI?
a) Indian Ayurveda research institute
b) Indian aeronautical research institute
c) Indian aerospace research institute
d) Indian agricultural research institute
Answer: d
Clarification: IARI stands for Indian agricultural research institute. It is located in New Delhi. This institute made the production of biogas at a very large scale possible by generating appropriate technologies for the production of biogas.

11. What is incorrectly marked in the following figure?

a) Slurry
b) Dung water
c) Gas holder
d) Digester
Answer: a
Clarification: The correct labelling of the biogas plant is shown in the following figure.

Methane accounts for about 50-70% of the biogas, Carbon-dioxide consists of about 30-40% and the rest of the gases like Hydrogen and hydrogen disulphide consists of only 10 % of the biogas.

250+ TOP MCQs on Biotechnological Applications in Medicine: Molecular Diagnosis and Answers

Biology Multiple Choice Questions on “Biotechnological Applications in Medicine: Molecular Diagnosis – 1”.

1. A person with the hereditary disease can be cured with the help of _________
a) gene therapy
b) cloning
c) dialysis
d) chemotherapy
Answer: a
Clarification: Gene therapy is a technique used to cure many hereditary diseases. It involves changing the genome in order to prevent or cure diseases. It is one of the most successful techniques used to cure hereditary diseases or to cure deficiency of various hormones.

2. A collection of methods that allows correction of a gene that has been diagnosed in child/embryo is called _________
a) cloning
b) gene therapy
c) chemotherapy
d) dialysis
Answer: b
Clarification: A collection of methods that allows the correction of a gene that has been diagnosed in a child/embryo is called gene therapy. It consists of various processes. In this, the defective genes are corrected and replaced with normal, healthy genes.

3. In gene therapy, the gene defects are cured in a child or ________ stage.
a) adult
b) teenage
c) old
d) embryo
Answer: d
Clarification: In gene therapy, the gene defects are cured in child or embryonic stage. This phase is chosen to avoid complications and each and every cell will receive a healthy, functional gene.

4. In gene therapy, the genetic defect is corrected by delivery of _______ gene into the individual.
a) incorrect
b) mutant
c) normal
d) jumping
Answer: c
Clarification: In gene therapy, the genetic defect is corrected by the delivery of a normal gene into the individual. This normal gene when replaced cures that deficiency. It is a functional gene and is useful in the curing of that disorder.

5. The inserted normal gene takes over the function of _________ gene.
a) correct
b) right
c) non-functional
d) functional
Answer: c
Clarification: In gene therapy, the inserted normal gene takes over the function of the non-functional gene. This non-functional gene is also called as an incorrect or mutant gene. This change in function is useful in successfully curing of the disease.

250+ TOP MCQs on Population Attributes – 2 and Answers

Biology Written Test Questions and Answers for Class 12 on “Population Attributes – 2”.

1. Which organisms are considered a population for the purpose of ecological studies?
a) Sexually reproducing organisms
b) Sexually as well as asexually reproducing organisms
c) Asexually reproducing organisms
d) Species
Answer: b
Clarification: For ecological studies of population, both sexually as well as asexually reproducing organisms are considered. The organisms formed from sexual reproduction are genetically different (except homozygotic twins). The organisms produced by asexual reproduction are genetically as well as morphologically similar.

2. Which of the following areas do population ecology links?
a) Ecology, population genetics, and evolution
b) Ecology, population genetics, and mathematics
c) Biology, physics and, history
d) Ecology, physics and, history
Answer: a
Clarification: Population ecology is a subject that studies the reasons, factors affecting population and how population change over time. It is important for biology conservation and it links ecology with population genetics and evolution.

3. Which of the following attribute does a population have?
a) Births
b) Birth rate
c) Deaths
d) Pyramid
Answer: b
Clarification: Among the given above birth rate is a population attribute. It is the number of individuals born in a population at a specific time. For humans, it is described as a number of individuals born per 1000 of the population per year.

4. Which of the following attribute does a population have?
a) Pyramid
b) Births
c) Deaths
d) Death rate
Answer: d
Clarification: Among the given above death rate is a population attribute. It is the number of individuals died in a population at a specific time. For humans, it is described as a number of deaths per 1000 of the population per year.

5. Which of the following attribute does a population have?
a) Deaths
b) Births
c) Sex ratio
d) Pyramid
Answer: c
Clarification: Among the given above sex ratio is a population attribute. It is the ratio of the number of males versus the number of females. Usually, the tendency of sexually reproducing organisms is to maintain a ratio of 1:1.

6. What does the plot of the age distribution of population results in?
a) Sex ratio
b) Age pyramid
c) Tree
d) Mountain
Answer: b
Clarification: When a plot of the age distribution of a population is made it results in a structure called age pyramid. It indicates the growth status of a population and tells whether a population is growing, stable or declining.

7. By which letter is the population density designated?
a) A
b) G
c) F
d) N
Answer: d
Clarification: The population density also known as population size is designated by the letter ‘N’. The population density tells about the number of individuals in a unit area (per square meter, per square kilometer or per hectare) at a specific time.

8. At which level does natural selection act?
a) Cellular level
b) Species level
c) Population level
d) Organism level
Answer: c
Clarification: Natural selection is a phenomenon that acts at a population level. Natural selection does not create mutations or variations rather it leads to the extinction of individuals who could not adapt to the changing environmental conditions.

9. On what basis is the tiger census in our national parks calculated?
a) Number of stripes
b) Number of legs
c) Number of limbs
d) Number of pug marks
Answer: d
Clarification: The tiger census in our national parks calculated on the basis of the number of pug marks. It is one of the most popular techniques to calculate the number of tigers. According to 2018 reports, the tiger population has increased up to 3000.

10. On what basis is the tiger census in our national parks calculated?
a) Number of stripes
b) Fecal pellets only
c) Number of pug marks and fecal pellets
d) Number of limbs
Answer: c
Clarification: The tiger census in our national parks calculated on the basis of the number of pug marks and fecal pellets which helps in determining the number of tigers along with their species. According to 2018 reports, the tiger population has increased up to 3000.

11. In which of the following case is the number of old people more?
a) Growing population
b) Declining population
c) Steady population
d) Reproductive population
Answer: b
Clarification: The population has a large number of individuals in a post-reproductive age is called a declining population. It is so-called because it has more number of old individuals, there will be fewer births and more deaths thus indicating negative population growth.

12. In which of the following case is the number of children (0-14years) more?
a) Steady population
b) Declining population
c) Expanding population
d) Reproductive population
Answer: c
Clarification: The expanding population has more number of children between 0-14years. It is the pre-reproductive age. It is so-called because fertile females can give rise to more children thus increasing the population.

13. Which of the following age pyramid indicates an expanding population?
a)

b)

c)

d)

Answer: a
Clarification: An expanding population has a triangular-shaped pyramid. In this, the individuals in pre-reproductive age are more, moderate in reproductive age while fewer individuals are present in post-reproductive age.

14. Which of the following age pyramid indicates a declining population?
a)

b)

c)

d)

Answer: d
Clarification: The declining population has an urn-shaped pyramid. In this, more individuals are present in reproductive age as compared to pre-reproductive age. It indicates the negative growth of the population.

15. Which of the following age pyramid indicates a steady population?
a)

b)

c)

d)

Answer: b
Clarification: A steady population has a bell-shaped pyramid. In this, the individuals in pre-reproductive and reproductive age are almost equal while fewer individuals are present in post-reproductive age.

To practice Biology Written Test Questions and Answers for Class 12,

250+ TOP MCQs on Ecosystem – Energy Flow and Answers

Biology Multiple Choice Questions on “Ecosystem – Energy Flow – 1”.

1. What the only source of energy for all ecosystems on Earth?
a) Water
b) Sun
c) Plants
d) Animals
Answer: b
Clarification: The only source of energy for all ecosystems on Earth is the sun. The radiant light and heat from the sun is the primary, original source for most of the organisms and is used for the production of electricity, fuel, thermal energy, agriculture, etc.

2. Which is an exception in an ecosystem where the sun is not the source of energy?
a) Deep-sea hydro-thermal ecosystem
b) Terrestrial ecosystem
c) Lake ecosystem
d) Desert ecosystem
Answer: a
Clarification: The deep-sea hydro-thermal ecosystem is an exception in the ecosystem where the sun is not the source of energy. The chemosynthesis, marine snow, and whale falls are the three main sources of energy and nutrients for deep-sea communities.

3. What is the spectral range of solar radiation in that photosynthetic organisms are able to use in the process of photosynthesis called?
a) Photosynthetically Reactive Radiation
b) Photosynthetically Active Radiation
c) Photosynthetically Deactive Radiation
d) Photosynthetically Trapped Radiation
Answer: b
Clarification: The spectral range of solar radiation in that photosynthetic organisms are able to use in the process of photosynthesis is called as Photosynthetically Active Radiation. It is designated as PAR and ranges from 400nm to 700nm.

4. What percent of the incident solar radiation is photosynthetically active radiation (PAR)?
a) 100%
b) 85%
c) 20%
d) 50%
Answer: d
Clarification: Almost less than equal to the 50% of the incident solar radiation is photosynthetically active radiation (PAR). It ranges from 400nm to 700nm.

5. What percent of PAR is captured by plants?
a) 1%
b) 20-30%
c) 2-10%
d) 50%
Answer: c
Clarification: The spectral range of solar radiation that photosynthetic organisms are able to use in the process of photosynthesis is called PAR (400 to 700nm). Almost 2-10% of PAR is captured by plants.

6. On what are the organisms are dependent on their food?
a) Consumers
b) Producers
c) Decomposers
d) Scavengers
Answer: b
Clarification: All organisms directly or indirectly are dependent on producers for their food production. Producers are organisms that make their own food with the help of energy obtained from chemicals or the sun, water, and air. They are also known as autotrophs.

7. How is the flow of energy from the sun to producers and then to consumers?
a) Multidirectional
b) Bidirectional
c) No direction
d) Unidirectional
Answer: d
Clarification: The movement of energy from the higher trophic levels and its distribution and loss as heat to the lower trophic levels in the environment is unidirectional. It means the energy moves in one direction only that is from higher to the lower-most level.

8. From which law of energy the ecosystem are not exempted?
a) Zeroth law
b) First law of thermodynamics
c) Second law of thermodynamics
d) Fifth law of thermodynamics
Answer: c
Clarification: The ecosystems are not exempted from the Second Law of thermodynamics since they require a constant energy supply for synthesis of food. This increases the tendency toward disorderliness.

9. What are the green plants in the ecosystem termed as?
a) Scavengers
b) Consumers
c) Decomposers
d) Producers
Answer: d
Clarification: Usually the green plants present in the ecosystem are termed as the producers. Producers (autotrophs) are organisms that make their own food with the help of energy obtained from chemicals or the sun, water, and air.

10. Who are the major producers in a terrestrial ecosystem?
a) Phytoplankton
b) Zooplankton
c) Green plants
d) Birds
Answer: c
Clarification: The green plants (herbaceous and woody plants) are the major producers in a terrestrial ecosystem. Producers (autotrophs) are organisms that are capable of producing their own food (organic molecules) with the help of energy obtained from chemicals or the sun, water, and air (inorganic sources).

11. Who are the major producers in an aquatic ecosystem?
a) Zooplankton
b) Phytoplankton
c) Fungi
d) Bacteria
Answer: b
Clarification: Phytoplankton is the major producers in an aquatic ecosystem. Producers (autotrophs) are organisms that make their own food with the help of energy obtained from chemicals or the sun, water, and air.

12. How sunlight is much is reflected back out of the total sunlight reaching Earth?
a) 100%
b) 50%
c) 34%
d) 10%
Answer: c
Clarification: Almost 34 percent of light is reflected back out of the total sunlight reaching Earth. The heat and light from the sun is the original, primary source for most of the organisms and is used for the production of electricity, fuel, thermal energy, agriculture, etc.

13. How much percent of light reaches the Earth’s surface out of the total sunlight?
a) 20%
b) 56%
c) 0.1%
d) 30%
Answer: b
Clarification: Approximately 56-60 percent of light reaches the Earth’s surface out of the total sunlight. The heat and light from the sun is the original, primary source for most of the organisms and is used for the production of electricity, fuel, thermal energy, agriculture, etc.

14. What amount of sunlight is held the ozone layer, water vapor, and atmospheric gases out of total sunlight reaching Earth?
a) 50%
b) 8%
c) 20%
d) 10%
Answer: d
Clarification: 10% of sunlight is held the ozone layer, water vapor, and atmospheric gases out of total sunlight reaching Earth. The radiant light and heat from the sun is the primary, original source for most of the organisms.

15. What does this statement “The energy passed from producers to consumers (herbivores) does not go back to producers (autotrophs)” states about the flow of energy?
a) Flow is unidirectional
b) Flow has no specific direction
c) Flow is bidirectional
d) Flow is multidirectional
Answer: a
Clarification: The statement “The energy passed from producers to consumers (herbivores) does not go back to producers (autotrophs)” tells that the flow of energy is unidirectional. It means the energy moves in one direction only that is from higher to the lower-most level.

250+ TOP MCQs on Biodiversity Basics and Answers

Biology Multiple Choice Questions on “Biodiversity Basics”.

1. The Earth consists of how many ant species?
a) 100,000
b) 20,000
c) 200,000
d) 2000
Answer: b
Clarification: Ants are eusocial (highly social) insects. They live together in organized colonies. There are approximately 20,000 species of ants on the Earth.

2. How many species of beetles are present on the Earth?
a) 3,00,000
b) 30,000
c) 3,000
d) 300
Answer: a
Clarification: Beetles are a group of winged insects and eat almost everything. They are prominent decomposers, and there are approximately 3,00,000 species of beetles on the Earth.

3. How many species of fishes are present on Earth?
a) 28,00,000
b) 28,000
c) 280
d) 28
Answer: b
Clarification: Fishes are limbless cold-blooded vertebrate gill-bearing aquatic craniate animals. They commonly have fins and are covered with scales. There are approximately 28,000 species of fishes on Earth.

4. How many species of orchids are present on Earth?
a) 200
b) 20
c) 2
d) 20,000
Answer: d
Clarification: An orchid growing on epiphyte is an example of commensalism. Epiphytes grow on trees for air and sunlight while the tree is not harmed due to its presence. Another epiphyte growing on trees is a fern. There are approximately 20,000 species of orchids on Earth.

5. Which of the following statements is true?
a) Diversity exists only at the species level
b) Diversity exists only at the macromolecular level
c) Diversity exists at all levels of biological organization
d) Diversity exists at the genetic level only
Answer: c
Clarification: Biodiversity is the variety and variability of all the levels of biological organization (plant and animal life) on Earth. The diversity exists not only at the genetic level but at all levels of biological organization.

6. Who popularized the term biodiversity?
a) Rudolf Virchow
b) Edward Wilson
c) Gregor Mendel
d) Robert Koch
Answer: b
Clarification: Edward Wilson popularized the term biodiversity. Biodiversity is the variety and variability of all the levels of biological organization (plant and animal life) on Earth.

7. What can a single species show?
a) No variation at the genetic level
b) No diversity at the genetic level
c) Low diversity at the genetic level
d) High diversity at the genetic level
Answer: d
Clarification: Genetic diversity is important among various levels of biodiversity. High genetic diversity can be seen only in a single species.

8. What is the feature of the biosphere?
a) No diversity
b) Homogeneity
c) Heterogeneity
d) Negligible diversity
Answer: c
Clarification: Biosphere is the total surface and atmosphere integrating all living beings and their relationships of the Earth. The biosphere is heterogeneous in nature and shows immense diversity. Thus heterogeneity is a feature of the biosphere.

9. How many strains of rice does India have?
a) 50
b) 500
c) 5,000
d) 50,000
Answer: d
Clarification: India consists of approximately 50,000 strains of rice. Rice is an edible starchy cereal grain, seed of the grass species Oryza. Rice is said to be the most widely consumed staple food.

10. How many varieties of mango does India have?
a) 2
b) 10
c) 1,000
d) 20
Answer: c
Clarification: Mango is an edible stone fruit (drupe) belonging to the flowering plant genus Mangifera. They grow mostly in tropical areas. India consists of approximately more than 1,000 varieties of mango.

11. What is the feature of the biosphere?
a) No diversity
b) Species diversity
c) Low diversity
d) Negligible diversity
Answer: b
Clarification: The diversity observed at the species level is known as the species diversity. It is the number and abundance of each species in a particular area. Species diversity is one of the important features of the biosphere.

12. Which organism’s species have greater diversity in the Western Ghats than the Eastern Ghats?
a) Reptiles
b) Fishes
c) Amphibians
d) Mammals
Answer: c
Clarification: Amphibians have more species diversity in the Western Ghats than the Eastern Ghats. A chain of mountains running parallel to India’s western coast (Sahyadri) and the mountain ranges run parallel to the Bay of Bengal are the western and eastern ghats respectively.

13. What is the feature of the biosphere?
a) Low diversity
b) Ecological diversity
c) Negligible diversity
d) No diversity
Answer: b
Clarification: Ecological diversity is one of the important features of the biosphere. It deals with the variations in ecosystems and their overall impact on human existence and the environment within a geographical area.

14. How many years did evolution required?
a) Tens
b) Hundreds
c) Trillions
d) Millions
Answer: d
Clarification: Evolution is the result of the process of slow and gradual changes in millions of years. As evolution proceeds, organisms become more and more complex. The complexity of organisms can be given by studying various processes of biological organization.