Category: Class 12 Biology Objective Questions

Biology Multiple Choice Questions on “Venereal Diseases in Humans-1”.

1. Treponema pallidum is responsible for causing which of the following STD’s?
a) Syphilis
b) Gonorrhoea
c) Chancroid
d) Herpes
Answer: a
Clarification: Treponema pallidum is responsible for causes Syphilis. It is a bacterium. It is transmitted through sexual contact or exchange of blood or placenta to the foetus.

2. What is the full form of VDRL?
a) Venereal Diseases Resource Laboratory
b) Venereal Disease Research Laboratory
c) Virus Disorder Running Lab
d) Viral Diseases Resource Laboratory
Answer: b
Clarification: VDRL stands for Venereal Disease Research Laboratory. It is an antibody detection test used for diagnosing Syphilis. The VDRL test doesn’t look for the bacteria that cause syphilis. Instead, it checks for the antibodies our body makes in response to the antigens.

3. Which of the following is a venereal disease, caused by a virus and can get transmitted by blood contact also?
a) Syphilis
b) Hepatitis-B
c) Chancroid
d) Trichomoniasis
Answer: b
Clarification: Hepatitis-B is caused by Hepatitis B virus (HBV). It is also a venereal disease or a sexually transmitted disease. The virus passes from one person to another by blood, semen or any other body fluids.

4. In males, urethritis is the principal result of ________
a) Gonorrhoea
b) Syphilis
c) Chlamydia
d) Chancroid
Answer: c
Clarification: In males, urethritis is the principal result of Chlamydia. Symptoms of Urethritis include a thick discharge, burning on urination, frequent and painful urination.

5. The site of infection in case of Gonorrhoea can be all except _______
a) Throat
b) Vagina
c) penis
d) liver
Answer: d
Clarification: The site of infection relates to the type of sexual contact, occurring in mouth and throat after oral-genital contact, vagina and penis after genital contact or rectum after recto-genital contact.

6. Which of the following disease is caused by a protozoan?
a) Trichomoniasis
b) Gonorrhoea
c) Genital Warts
d) Chancroid
Answer: a
Clarification: Trichomoniasis is caused by Trichomonas vaginalis which is a flagellated protozoan. Trichomoniasis is an inflammation of the mucous membrane of the vagina in female and urethra in males.

7. The most common site of infection in female suffering from chlamydiasis is _______
a) Urethra
b) Ovaries
c) Cervix
d) Anus
Answer: c
Clarification: The most common site of infection in female suffering from chlamydiasis is the cervix, resulting in cervicitis and production of thick mucus and pus discharge.

8. Which of the following sexually transmitted disease is caused by yeast?
a) Enterobiasis
b) Syphilis
c) Scabies
d) Candidiasis
Answer: d
Clarification: Candidiasis is a fungal infection due to Candida (a genera of yeast). When it affects the vagina, a white cottage cheese-like discharge occurs along with genital itching and burning.

9. Urinogenital tract infection in males accompanied by yellow discharge, burning feeling on passing urine, fever and headache is ______
a) Gonorrhoea
b) Syphilis
c) Genital Herpes
d) Chancroid
Answer: a
Clarification: Urinogenital tract infection in males accompanied by yellow discharge, burning feeling on passing urine, fever and headache is Gonorrhoea. It is caused by the bacterium Neisseria gonorrhoeae. In males, prostate gland and epididymis may also become infected.

10. Sexually Transmitted disease affecting both male and female genitals which often damages the eyes of babies born to infected mothers is _________
a) AIDS
b) Genital Herpes
c) Syphilis
d) Gonorrhoea
Answer: d
Clarification: Gonorrhoea is a Sexually transmitted disease affecting both males and females’ genitals. If the bacteria causing Gonorrhoea are transmitted to the eyes of a new-born in the birth canal, blindness can result.

11. Which of the following is not a Sexually Transmitted Disease?
a) Muscular Dystrophy
b) Syphilis
c) Chancroid
d) Trichomoniasis
Answer: a
Clarification: Muscular Dystrophy is not a sexually transmitted disease. It is an autosomal dominant Mendelian disorder. Syphilis, Chancroid and Trichomoniasis are sexually transmitted diseases which are caused by Treponema pallidum, Haemophilus ducrei and Trichomonas vaginalis respectively.

12. Which of the following symptom can be related to the tertiary stage of syphilis?
a) The appearance of Chancre and rashes
b) When signs of organ degeneration appear
c) Very High fever and sore throat
d) Joint and muscle pain
Answer: b
Clarification: In the first stage of syphilis, Chancre and rashes appear. Fever along with muscle and joints pain occur in the secondary stage. These symptoms also disappear. During the symptomless period which lasts for about 20 years, the bacteria may invade the body organs. When the signs of organ degeneration appear, the disease is said to be in a tertiary stage.

Biology Multiple Choice Questions on “Human Health and Disease – Drugs and Alcohol Abuse-1”.

1. What is Drug Addiction?
a) Addiction to Food
b) Dependence on Drugs
c) Taking medicines with valid medical prescriptions
d) Not eating a balanced diet
Answer: b
Clarification: Drug addiction is the condition of a physical, physiological or psychological dependence on a certain drug or a combination of drugs due to its repeated use over a period of time. There is a tendency to increase the dose and an overpowering desire to obtain the dose by whatever means.

2. In which age group, Drug addiction is a major problem?
a) Childhood
b) Adolescence
c) Adulthood
d) Old Age
Answer: b
Clarification: Drug addiction is a common practice in Adolescence. As Adolescence is accompanied by several biological and physiological changes, it is the most vulnerable phase of mental and psychological development of an individual. Curiosity, need for adventure and experimentation motivates youngsters towards Drug and Alcohol abuse.

3. When is International Day Against Drug Abuse celebrated?
a) 26^th June
b) 12^th August
c) 14^th September
d) 1^st December
Answer: a
Clarification: In December 1987, the UN General Assembly decided to observe June 26 as the International Day Against Drug Abuse and Illicit Trafficking. Currently, according to the UN, nearly 200 million people are using illicit drugs.

4. Which of the following drugs is not used commonly by the youth?
a) Opioids
b) Cannabinoids
c) Coca Alkaloids
d) Orphan Drug
Answer: d
Clarification: The drugs which are commonly abused by the youth are Opioids, Cannabinoids and Coca Alkaloids. Majority of these are obtained from flowering plants. Some are obtained from fungi also.

5. Which of the following is not a symptom of mental illness?
a) Insomnia
b) Depression
c) Positive attitude
d) Delusions and hallucinations
Answer: c
Clarification: The various symptoms of mental illness are depression or mental state with a feeling of sadness, despair and discouragement. Insomnia or excessive sleep, apprehensive behaviour, Mood fluctuations from depression to elation, Inability to concentrate, Delusions and Hallucinations, Self-destructive behaviour, etc.

6. Which of the following is not a common problem of Adolescence?
a) Spirituality
b) Acne
c) Post-traumatic Stress Disorder
d) Mood Swings
Answer: a
Clarification: Common problems of Adolescence include Acne, Mood fluctuations, Post-Traumatic Stress disorder which is a mental disorder which is as a result of traumatic events like rape, assault, natural disasters, etc.

7. Legally Drug Abuse is the intake of drugs with valid medical prescriptions and for Medical purposes.
a) True
b) False
Answer: b
Clarification: Legally Drug Abuse is the intake of drugs without valid medical prescriptions and for Non-medical purposes. Drug abuse is for obtaining pleasure or euphoria and is done in such amount or frequency that damages the physical and mental functioning of an individual.

8. What is Hypochondria?
a) Mental Disorder
b) Physical Disorder
c) Physiological Disorder
d) Social Disorder
Answer: a
Clarification: Hypochondria is a mental disorder in which the patient is preoccupied with body functions and normal sensations finding faults and seeking medical attention. Hypochondria usually occurs in late developer adolescents due to anxiety syndrome.

9. What are Obsessive-Compulsive Disorders?
a) Mental Disorders
b) Psychological Disorders
c) Personality Disorder
d) Mental Behaviour
Answer: b
Clarification: Obsessive-Compulsive Disorders are psychological disorders characterised by recurrent obsessions or compulsions, severe enough to interfere with a person’s working hours, personal or social functioning. The common obsessions are constant doubts, violence, contamination by dirt and germs.

10. Which of the following is not a common symptom of Schizophrenia?
a) Auditory hallucinations
b) Laughing and Crying at inappropriate occasions
c) Progressive growth of personality
d) The shallowness of emotional life
Answer: c
Clarification: The common symptoms of Schizophrenia include Progressive deterioration of personality, Laughing and crying at inappropriate occasions, Distorted thoughts, auditory hallucinations, delusions, sense of being influenced by others, Shallowness of emotional life. As the schizophrenics suffer from delusions and hallucinations, they are unable to perform even simple jobs.

11. What is Borderline Personality Disorder (BPD)?
a) Personality Disorder
b) Social Disorder
c) Physiological Disorder
d) Mental Wellbeing
Answer: a
Clarification: Borderline Personality Disorder is an emotionally unstable personality disorder where the patient suffers from impulsively unpredictable moods, an outburst of emotions, uncontrolled anger, impulsive and self-damaging acts and repeated conflicts with others.

12. Which of the following is not a symptom of BPD?
a) Cognitive instability
b) Behavioural dysregulation
c) Emotional instability
d) Euphoria
Answer: d
Clarification: BPD is characterised by a specific pattern of behavioural, emotional, cognitive instability and dysregulation. The individuals over-react with a problem of anger and anger expression. There are episodes of depression, anxiety and irritability. The patients have a fear of abandonment.

13. Psychoactive drugs have the ability to alter the activities of the nervous system.
a) True
b) False
Answer: a
Clarification: Addictive drugs are also called as psychoactive drugs because they have the ability to alter the activity of the nervous system. These drugs are habit-forming. They alter perception, behaviour and consciousness.

14. Which of the following was a major reason for the development of Drugs?
a) For clinical purposes
b) To experience hallucinations
c) Adventure
d) For curiosity
Answer: a
Clarification: Most of the drugs were developed for clinical purposes. However, they are being used for a purpose other than clinical use, in an amount, concentration and frequency that impairs the body’s physical, physiological and psychological functions. It is called Drug Abuse.

15. Which of the following is not a common reason for Drug Abuse or Drug Dependence?
a) Peer Pressure
b) Adventure
c) A feeling of Excitement and Euphoria
d) For death
Answer: d
Clarification: People don’t use drugs to simply die. They use it to die eventually. The reasons for Drug Abuse include Peer Pressure, Overcoming frustration or depression, for Adventure, for a feeling of pleasure, excitement and Euphoria.

Biology Multiple Choice Questions on “Bacterial Diseases in Animals”.

1. Which of the following organism causes pneumonia?
a) Bacteria
b) Protozoan
c) Fungi
d) Slime mould
Answer: a
Clarification: Pneumonia is caused by bacteria Streptococcus pneumoniae or Diplococcus pneumoniae. Klebsiella pneumoniae and few other bacteria also cause pneumonia. Antibiotic treatment is helpful.

2. Which of the following is not a characteristic of pneumonia in animals?
a) Inflammation of lungs
b) Accumulation of mucus in alveoli
c) Fever
d) Easy breathing
Answer: d
Clarification: Pneumonia is a disease of lungs which is characterised by inflammation of lungs and accumulation of mucus in alveoli and bronchioles that makes breathing quite difficult. Fever, chill and rapid shallow breathing are also observed.

3. Mastitis refers to _________
a) Inflammation of nephrons
b) Inflammation of neurons
c) Inflammation of Udders
d) Inflammation of mast cells
Answer: c
Clarification: Mastitis is an inflammation of udders that often occurs in dry cows and pre-calving heifers due to infection of bacterium Corynebacterium pyogenes. The antibiotic treatment provides cure.

4. Which of the following is a highly contagious bacterial disease of cattle?
a) Mastitis
b) Anthrax
c) Pneumonia
d) Typhoid
Answer: b
Clarification: Anthrax is a highly contagious bacterial disease of cattle, buffalo, horse, sheep, goat, etc. which is caused by rod-shaped bacterium called Bacillus anthracis.

5. Anthrax does not spread to humans while handling infected animals.
a) False
b) True
Answer: a
Clarification: Anthrax spreads through contact with infected animals, contaminated feed, contaminated water and pasture. It also infects human beings handling infected animals and their products.

6. Which of the following is not a symptom of Anthrax?
a) Rapid Breathing
b) Low body temperature
c) Discharge from nostrils
d) Rapid heartbeat
Answer: b
Clarification: Symptoms of Anthrax include high fever, rapid breathing, congestion, painful swellings in different body parts, blood mixed foamy discharge from nostrils and later from mouth and anus. The body temperature also becomes high. Rapid heartbeats and breathing are also observed.

7. In anthrax, when discharge from natural opening becomes black, shining or foamy, death of the animal is likely to occur within 2-3 days.
a) True
b) False
Answer: a
Clarification: In anthrax, when discharge from natural opening becomes black, shining or foamy, death of the animal is likely to occur within 2-3 days. Death occurs mostly due to the consumption of blood carried oxygen by the bacterium. The bacterium can be observed under microscope from blood samples of diseased animals.

8. Which of the following is not a preventive measure for Anthrax?
a) Vaccination
b) Antiserum injection
c) Dirty pastures
d) Carcasses should be effectively disposed
Answer: c
Clarification: Preventive measures include vaccination and antiserum injection to all, if the disease is noticed in any of the animals of the pasture. Carcasses should be effectively disposed off to prevent dispersal of anthrax spores.

9. Which of the following microorganism causes a bacterial disease in a poultry farm?
a) Ascaridia galli
b) Mycobacterium avium
c) Eimeria
d) Paramyxovirus
Answer: b
Clarification: Mycobacterium avium is a bacterium which causes Tuberculosis. Ascaridia galli, Eimeria and Paramyxovirus Cause Fowl Ascariasis, Coccidiosis and New castle disease respectively.

10. Which of the following is not a bacterium which causes disease in a poultry farm?
a) Tapeworm
b) Haemophilus gallinarium
c) Salmonella gallinarium
d) Pasteurella avicida
Answer: a
Clarification: Many species of tapeworm causes Taeniasis. Salmonella gallinarium causes Fowl typhoid or Salmonellosis. Haemophilus gallinarium causes Fowl coryza. Pasteurella avicida causes Fowl cholera.

Biology Online Quiz for Schools on “Microbes in Industrial Products-2”.

1. Who coined the term antibiotics?
a) Waksman
b) Pasteur
c) Babes
d) Albert
Answer: a
Clarification: The term antibiotics was coined by Waksman in 1942. Clinically, an antibiotic is a substance produced by a microorganism which is in low concentration and inhibits the growth and metabolic activity of pathogenic organisms without harming the host.

2. Who was the first person to discover an antibiotic?
a) Rene Dubois
b) Alexander Fleming
c) Waksman
d) Louis Pasteur
Answer: b
Clarification: The first antibiotic is generally associated with the name of Alexander Fleming when he discovered Penicillin from Penicillium notatum in 1928. Penicillium notatum did not allow the growth of Staphylococcus aureus.

3. Broad-spectrum antibiotics can kill only a small number of pathogens.
a) True
b) False
Answer: b
Clarification: Broad Spectrum antibiotic is an antibiotic which can kill or destroy several pathogens that belong to different groups with different structures and wall composition.

4. Which of the following is not a method by which antibiotic functions?
a) Disruption of wall synthesis
b) Inhibition of 50S ribosome
c) Inhibition of DNA synthesis
d) Permitting the growth of bacteria
Answer: d
Clarification: Antibiotic functions by the disruption of wall synthesis of bacteria, Inhibition of 50 S ribosome function, Inhibition of translation, Inhibition of DNA synthesis, Disruption of plasmalemma repair and synthesis, etc.

5. Which of the following is not the characteristic of a good antibiotic?
a) Harmless to host
b) Ability to destroy the pathogen
c) Ability to destroy all the microflora in the alimentary canal of the host
d) Effective against all strains of pathogens
Answer: c
Clarification: A good antibiotic is harmless to host with no side effects, harmless to normal microflora of the alimentary canal of the host, Ability to destroy all strains of the pathogen and has a quick action.

6. Which of the following may be a reason for the development of resistance to antibiotics?
a) Mutation in the pathogen
b) Very effective antibiotic
c) Very weak pathogen
d) Can never happen
Answer: a
Clarification: Pathogens often develop resistance to existing antibiotics so that newer antibiotics are required to be produced. The resistance is produced due to the development of copious mucilage, Alternation of the cell membrane of bacteria which prevents antibiotic entry and mutation in the pathogen.

7. From which of the following species an antibiotic is generally not obtained?
a) Lichens
b) Fungi
c) Actinomycetes
d) Archaebacteria
Answer: d
Clarification: Antibiotics are generally obtained from lichens, fungi, eubacteria and actinomycetes. Over 7000 antibiotics are known. Every year some 300 new antibiotics are discovered using hypersensitive microorganisms.

8. Which of the following is a common antibiotic obtained from lichens?
a) Usnic acid
b) Penicillin
c) Cephalosporium
d) Clavacin
Answer: a
Clarification: The common antibiotics obtained from lichens is usnic acid from Usnea and Cladonia. Fungi yield several antibiotics like penicillin, polyporin, clavacin, clitocybin, etc.

9. For which of the following purpose, antibiotics are not used?
a) For killing essential bacteria
b) As medicines
c) As preservatives
d) As feed supplements
Answer: a
Clarification: Antibiotics are not used for killing essential bacteria. They are used as medicines, preservatives in perishable food articles and as feed supplements for animals especially poultry birds.

10. Streptomyces is an antibiotic obtained from actinomycetes.
a) True
b) False
Answer: a
Clarification: Streptomyces is an antibiotic obtained from actinomycetes. Other antibiotic yielding actinomycetes are Streptoverticillium, Micromonospora, Nocardia, Actinoplanes, etc.

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Biology Multiple Choice Questions on “Biotechnology Applications – Pest Resistant Plants – 1”.

1. Which nematode infects the roots of tobacco plants?
a) Meloidogyne incognitia
b) Ditylenchus dipsaci
c) Xiphinema index
d) Nacobbus aberrans
Answer: a
Clarification: Meloidogyne incognitia is the nematode that infects the roots of tobacco plants. It is also known as ‘root-knot nematode’. It is a plant-parasitic nematode. It affects both monocots as well as dicot plants.

2. Which one is the method of cellular defense in animals and plants?
a) Recombinant DNA technology
b) RNA interference
c) Immune response
d) Mutation
Answer: b
Clarification: RNA interference is one of the cellular defense mechanisms found in animals and plants. It defends against viruses and transposable elements. In this method, short RNA stretches are used (20-30 nucleotides).

3. RNAi stands for ______
a) RNA intersection
b) RNA insertion
c) RNA intercom
d) RNA interference
Answer: d
Clarification: RNAi stands for RNA interference. It is a series of processes in which short RNA sequences are used to recognize and manipulate complementary nucleic acids. These short RNA sequences consist of 20-30 nucleotides. It protects against viruses and transposable elements.

4. _________ is mobile genetic elements.
a) Viruses
b) Bacteria
c) Transposons
d) Insertion sequences
Answer: c
Clarification: Transposons are mobile genetic elements and are also known as jumping genes. These are the sequences of DNA that can move from one position to another within the genome. They were first discovered by Barbara McClintock in maize plants.

5. ______ vectors are used for the introduction of nematode specific genes in the host.
a) Bacterial
b) Viral
c) Agrobacterium
d) Meloidogyne incognitia
Answer: c
Clarification: Agrobacterium vectors are used for the introduction of nematode specific genes in the host. This was uses for RNAi technique. Initially, the host plant used was a tobacco plant.

6. A method involving silencing of specific mRNA due to the binding of complementary dsRNA is called ________
a) Electrophoresis
b) RNAi
c) rDNA technology
d) DNAi
Answer: b
Clarification: RNAi is a method involving the silencing of specific mRNA due to the binding of complementary dsRNA. It consists of various processes. It acts as a defense mechanism against viruses and transposable elements.

7. _______ prevents the translation of the mRNA.
a) Enhancing
b) Knock out
c) Clearing
d) Silencing
Answer: d
Clarification: Silencing prevents the translation of the mRNA. It regulates the expression of a gene by preventing its expression. This is used in the RNAi technique. It is a method used for knowing the function of the gene.

8. In RNAi, the DNA is introduced into a host plant in such a way that it produces both ________
a) complementary DNA and mRNA
b) mRNA and sense RNA
c) sense and antisense RNA
d) DNA and RNA
Answer: c
Clarification: RNAi stands for RNA interference. RNAi is a method involving the silencing of specific mRNA due to the binding of complementary dsRNA. In RNAi, the DNA is introduced into a host plant in such a way that it produces both sense and antisense RNA.

9. Sense and antisense RNA are _______ to each other.
a) similar
b) same
c) complementary
d) different
Answer: c
Clarification: The strand having sequence exact same to that of mRNA is called sense strand. The antisense strand consists of a complementary sequence that of transcribed mRNA. Antisense strand serves the template for the transcription, thus sense and antisense RNA are complementary to each other.

10. Sense and antisense RNA forms _____
a) ds RNA
b) ss RNA
c) ds DNA
d) ss DNA
Answer: a
Clarification: The sense and antisense RNA forms ds RNA. The sense strand has sequence same as that of mRNA which codes for a functional protein while the antisense strand consists of complementary nucleotides as that of the sense strand.

11. Formation of _______ initiates RNAi process.
a) ds DNA
b) ssDNA
c) ss RNA
d) ds RNA
Answer: d
Clarification: Formation of ds RNA initiates the RNAi process. RNAi is a series of processes that involve the silencing of mRNA sequence which prevents translation of that sequence. It is a widely used technique used for gene silencing.

12. RNAi takes place in all prokaryotic organisms.
a) True
b) False
Answer: b
Clarification: RNAi is a series of processes that involve the silencing of mRNA sequence which prevents translation of that sequence. It takes place in all eukaryotes like animals, plants, and fungi. It is not seen in prokaryotes.

Biology Exam Questions and Answers for Class 12 on “Organisms and Populations – Responses to Abiotic Factors – 2”.

1. What is diapause?
a) Shedding of leaves
b) Stage of suspended development
c) Aging in mammals
d) Programmed cell death
Answer: b
Clarification: Diapause is a stage of suspended development. It is like hibernation in higher animals except it is used to avoid hot, dry summers in tropical areas. It is done by the zooplankton species in lakes and ponds under unfavorable conditions.

2. What is the suspension of metabolic activities during summer called?
a) Aestivation
b) Diapause
c) Menopause
d) Regulation
Answer: a
Clarification: The suspension of metabolic activities during summer is called aestivation. It is prolonged dormancy and is also known as summer sleep. It helps in maintaining body temperature and avoids water loss in mostly cold-blooded animals such as snails, bees, tortoise, crocodile, etc.

3. What is maintaining the constancy of the internal environment called?
a) Conformation
b) Homeostasis
c) Adaptation
d) Migration
Answer: b
Clarification: Homeostasis is maintaining the constancy of the internal environment according to changing the external environment. It is a self-regulating process done by all organisms.

4. What are birds and mammals?
a) Thermoconfirmers and osmoconfirmers
b) Thermoconfirmers and osmoregulators
c) Thermoregulators and cold-blooded animals
d) Thermoregulators and osmoregulators
Answer: d
Clarification: All mammals and birds are thermoregulators and osmoregulators. These are the organisms the organism in which body temperature and the osmotic concentration of the body fluid changes with the ambient temperature and change with that of the ambient water osmotic concentration respectively.

5. What are most of the invertebrates?
a) Thermoregulators
b) Osmoregulators
c) Thermoconformers
d) Conformers
Answer: c
Clarification: Thermoconformers are the organisms whose body temperature changes according to changing environmental temperatures. They do not carry out thermoregulation. They are usually cold-blooded animals.

6. Why small animals are rarely found in polar regions?
a) Less loss of heat
b) Their surface area and body mass ratio is high
c) Their surface area and body mass ratio is low
d) Their surface area is small
Answer: b
Clarification: The small animals are rarely found in polar regions because they have a high surface area and body mass ratio. This is to more loss of heat and thus regulating their body temperature becomes difficult.

7. The Siberian cranes migrate to which National Park in India?
a) Kaziranga National Park, Assam
b) Silent Valley National Park, Kerala
c) Chikla Lake Bird Sanctuary, Orissa
d) Keoladeo National Park, Rajasthan
Answer: d
Clarification: Many birds from Siberia migrate to Keoladeo National Park, Bharatpur, Rajasthan. These Siberian cranes usually migrate during the onset of the autumn season and then return to arctic tundra for breeding around the end of April and the beginning of May.

8. Which rule states that in a cold climate, mammals possess shorter ears and limbs to minimize the heat loss?
a) Bergman’s rule
b) Blackman’s rule
c) Allen’s rule
d) Lindeman’s rule
Answer: c
Clarification: Allen’s rule is an eco-geographical rule which states that in a cold climate, mammals possess shorter ears and limbs to minimize heat loss. It was stated by Joel Asaph Allen in 1877. It is a form of an adaptation done for survival in colder regions.

9. What do the desert lizards do when their body temperature drops?
a) They burrow in the sand
b) They hide in the soil
c) They move in a shady place
d) They bask in the sun
Answer: d
Clarification: The desert lizards are cold-blooded animals that cannot regulate their body temperature. They bask in the sun when their body temperature drops to regulate their temperature to perform various metabolic activities.

10. Which process do some snails and fishes undergo to prevent themselves from desiccation?
a) Dormancy
b) Migration
c) Aestivation
d) Hibernation
Answer: c
Clarification: None.

11. For which of the following organisms thermoregulation is energetically expensive?
a) Large-sized aquatic animals
b) Small-sized terrestrial animals
c) Large-sized terrestrial animals
d) Medium-sized terrestrial animals
Answer: b
Clarification: Thermoregulation is energetically expensive for small-sized terrestrial animals because of their small size. The smaller is the animals; more is the heat loss from the body. The examples of small animals are humming birds, shrews, etc.

12. In which of the following, organisms completely stop their metabolic activities?
a) Hibernation
b) Aestivation
c) Death
d) Diapause
Answer: c
Clarification: The organisms stop their metabolic activities completely after death. In all others such as hibernation, aestivation, diapause the metabolic activities of organisms are slowed temporarily to avoid the loss of energy.

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