11. In how many parts is the human brain divided?
[A] 2
[B] 4
[C] 3
[D] 5
Show Answer
Correct Answer: C [3]
Notes:
The brain has three main parts: the cerebrum, cerebellum and brainstem. Cerebrum: is the largest part of the brain and is composed of right and left hemispheres.
12. The messages received by and transmitted from the brain to the various parts of the body take the form of which of the following impulses? (UPSC Prelims 1983)
[A] Nervous impulses
[B] Chemical impulses
[C] Mechanical impulses
[D] Automatic impulses
Show Answer
Correct Answer: A [Nervous impulses]
Notes:
The message to the brain form any body part takes the form of nervous impulses. Nerve impulses are mostly electrical signals along the dendrites to produce a nerve impulse or action potential. The action potential is the result of ions moving in and out of the cell.
13. Which of the following is the thermoregulatory centre of the man body? (UPSC Prelims 1991)
[A] Pituitary
[B] Skin
[C] Hypothalamus
[D] Thyroid
Show Answer
Correct Answer: C [Hypothalamus]
Notes:
The thermoregulatory center in the hypothalamus controls the temperature at which the human body operates. There are two sets of thermoreceptors involved in the controlling of the body temperature.
14. Which one of the following is not an essential micronutrient for plants? (UPSC Prelims 1996)
[A] Boron
[B] Zinc
[C] Sodium
[D] Copper
Show Answer
Correct Answer: C [Sodium]
Notes:
There are 13 essential nutrients required by plants for its healthy and proper growth. Now these nutrients are divided into two categories:
Macronutrients (nitrogen, phosphorus, potassium, calcium, magnesium and sulphur)
Micronutrients (iron, copper, manganese, zinc, boron, molybdenum and chlorine)
Additional mineral nutrient elements which are beneficial but not necessary are sodium, cobalt, vanadium, nickel, solenium, aluminium and silicon. Thus boron, zinc and copper falls into category of essential micronutrients while sodium does not.
15. Epiphytes are plants which depend on other plants for? (UPSC Prelims 2001)
[A] food
[B] mechanical support
[C] shade
[D] water
Show Answer
Correct Answer: B [mechanical support]
Notes:
They are an important source of food for many species. Typically, the older parts of a plant will have more epiphytes growing on them. Epiphytes differ from parasites in that they grow on other plants for physical support and do not necessarily affect the host negatively.
16. Which of the following features of DNA makes in uniquely suited to store and transmit genetic information from generation to generation? (UPSC Prelims 2001)
[A] Complementarity of the two stands
[B] Double helix
[C] Number of base-pairs per turn
[D] Sugar-phosphate backbone
Show Answer
Correct Answer: A [Complementarity of the two stands]
Notes:
Complementary base pairing in the DNA double helix (with its complementary DNA strands) describes the manner in which deoxyribose- nucleotides bind to each other. Essentially it means that the bases are arranged along the molecule such that the chains fit together snugly so as to be lightly secured by hydrogen bonds.
17. Among living organisms, which one of the following is the most responsible factor for bringing about the origin of a new species? (UPSC Prelims 2002)
[A] Isolation
[B] Mutation
[C] Natural Selection
[D] Sexual Reproduction
Show Answer
Correct Answer: A [Isolation]
Notes:
Origin of new species depends on isolation of gene flow between new species and develops significant genetic divergence.
18. Which of the following is studied in Ethnobotany?
[A] Practical use of plants by local culture and people
[B] Relations between Plants and peoples Behvaior
[C] Comparison of different plants in a particular area
[D] Study of relations of plants, animals and animals in an area
Show Answer
Correct Answer: A [Practical use of plants by local culture and people]
Notes:
Ethnobotany is the study of the plants of an area and their practical uses through the traditional knowledge of a local culture and people.
19. Which of the following branch of biology deals with the study of Cartilage?
[A] Chondrology
[B] Chromatology
[C] Cnidology
[D] Conchology
Show Answer
Correct Answer: A [Chondrology]
Notes:
Chondrology is the branch of anatomy that deals with cartilage.
20. Who discovered cell differentiation?
[A] Walther Flemming
[B] Edwin John Butler
[C] Karl Ernst von Baer
[D] Parthasarthy Iyengar
Show Answer
Correct Answer: A [Walther Flemming]
Notes:
Cell differentiation is the process by which dividing cells change their functional or phenotypic type. All cells probably derive from stem cells and acquire their functions when they mature. Walther Flemming discovered cell differentiation.
