11. Which of the following forms of Nitrogen is taken up by Higher Plants? (UPSC Prelims 1980).
[A] Nitrites only
[B] Nitrates only
[C] Nitrates and ammonia
[D] Urea
Show Answer
Correct Answer: B [Nitrates only]
Notes:
Plants do not get their nitrogen directly from the air. Plants absorb nitrogen from the soil in the form of nitrate (NO3−) and ammonium (NH4+). Nitrate is the form of nitrogen most used by plants for growth and development. Nitrate is the form that can most easily be lost to groundwater.
Nitrogen is a component of chlorophyll and therefore essential for photosynthesis. It is also the basic element of plant and animal proteins, including the genetic material DNA and RNA, and is important in periods of rapid growth. Plants use nitrogen by absorbing either nitrate or ammonium ions through the roots.
12. Which among the following acts as a resistance against disease in the body? (UPSC Prelims 1982)
[A] Vitamins
[B] Carbohydrates
[C] Red Corpuscles
[D] White Corpuscles
Show Answer
Correct Answer: D [White Corpuscles]
Notes:
White blood cells help you fight infection. When one gets sick, white blood cell count is higher than normal. This is because your body is releasing more of these cells to fight the infection.
13. Bile is secreted by which of the following organs? (UPSC Prelims 1985)
[A] Liver
[B] Gall bladder
[C] Kidney
[D] Pancreas
Show Answer
Correct Answer: A [Liver]
Notes:
Bile or gall is a dark green to yellowish brown fluid, produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver and stored and concentrated in the gallbladder.
14. The saliva helps in the digestion of which of the following materials? (UPSC Prelims 1988)
[A] Starch
[B] Proteins
[C] Fibers
[D] Fats
Show Answer
Correct Answer: A [Starch]
Notes:
The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin. Thus, digestion of food occurs within the mouth, even before food reaches the stomach.
15. For developing in bred lines in farm animals, following factors are taken into consideration:
- The crossbreds should be of outstanding type.
- They should not carry any detrimental genes.
- Progeney tested animals.
- Herd size should be large.
Of the statements given above, which one of the following combinations of factors is most essential? (UPSC Prelims 1990)
[A] 1 and 3
[B] 2 and 3
[C] 1 and 4
[D] 2 and 4
Show Answer
Correct Answer: D [2 and 4]
Notes:
Inbreeding results in homozygosity, which can increase the chances of offspring being affected by deleterious or recessive traits. This usually leads to at least temporarily decreased biological fitness of a population which is its ability to survive and reproduce. So for inbreeding they should not carry any detrimental genes and it is effective only if the herd is large.
16. In the context of the organic evolution, the loss of limbs of snakes is explained by which of the following phenomenon? (UPSC Prelims 2002)
[A] Use and disuse of organs
[B] adaptation to living in burrows
[C] natural selection
[D] inheritance of acquired characters
Show Answer
Correct Answer: A [Use and disuse of organs]
Notes:
In organic evolution, Lamarck believed that any particular part of the body that is put into more frequent use has tendency to develop stronger and better while that part of body which is put into less or no use has tendency to gradually disappear. So, loss of limbs in snake is an example of use and disuse of organs.
17. Which branch of biology is known for the scientific study of the distribution of animals on Earth?
[A] Phytogeography
[B] Zoogeography
[C] Psychobiology
[D] Zoophytology
Show Answer
Correct Answer: B [Zoogeography]
Notes:
Zoogeography is the branch of biogeography that deals with the geographical distribution of animal species.
18. Which of the following branch of biology deals with the study of behavioral aspects of animals?
[A] Myrmecology
[B] Palaeozoology
[C] Psychobiology
[D] Parazoology
Show Answer
Correct Answer: C [Psychobiology]
Notes:
Psychobiology is branch of biology which deals with the study of behavioral aspects of animals.
19. Who is the father of Modern Embryology?
[A] Antonie Van Leeuwenhoek
[B] Stephen Hales
[C] Karl Ernst von Bayer
[D] Georges Cuvier
Show Answer
Correct Answer: C [Karl Ernst von Bayer]
Notes:
Karl Ernst von Bayer was a Prussian-Estonian embryologist who discovered the mammalian ovum and notochord and founded the new science of comparative embryology with comparative anatomy.
20. Which of the following was invented by Jonas Salk?
[A] Polio Drop
[B] Polio Vaccine
[C] BCG Vaccine
[D] aspirin
Show Answer
Correct Answer: B [Polio Vaccine]
Notes:
The first effective polio vaccine was developed in 1952 by Jonas Salk. Polio, or poliomyelitis, is a disabling and life-threatening disease caused by the poliovirus.
