11. Which plants grow well only in light?
[A] Heliophytes
[B] Xerophytes
[C] Sciophilous
[D] Epiphytes
Show Answer
Correct Answer: A [Heliophytes]
Notes:
Sunstroke plants or heliophytes are adapted to a habitat with a very intensive insolation, because of the construction of its own structure and maintenance. Heliophytes, for example, are mullein, ling, thyme and soft velcro, white clover, and most roses.
12. Which of the following is the later (Second) formed primary xylem elements?
[A] Xylem fibres
[B] Metaxylem
[C] Xylem parenchyma
[D] Protoxylem
Show Answer
Correct Answer: B [Metaxylem]
Notes:
Metaxylem is the part of the primary xylem that differentiates after the protoxylem and that is distinguished typically by broader tracheids and vessels with pitted or reticulate walls.
13. Which of the following crops has the highest photosynthetic activity?
[A] Cotton
[B] Sugarcane
[C] Rice
[D] Wheat
Show Answer
Correct Answer: B [Sugarcane]
Notes:
Among the above all, the sugarcane has the highest photosynthetic activity. Photosynthesis is a chemical process that occurs in many forms of bacteria and virtually all plants, including aquatic plants and algae. The rate of photosynthesis in a plant is dependent on the environmental changes, as well as to intrinsic features of plant. The photosynthetic rate in sugarcane is directly related with the variation of solar radiation during the day.
14. 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.
15. Which among the following is responsible for the red colour of blood?
[A] Haemoglobin
[B] Platelets
[C] Plasma
[D] None of the above
Show Answer
Correct Answer: A [Haemoglobin]
Notes:
Haemoglogin pigment is responsible for the red colour of the blood. Haemoglobin is responsible for carrying oxygen from lungs to the tissues of the body.
16. What is the scientific name of sea fan?
[A] Psittaciformes
[B] Pavo cristatus
[C] Alcyonacea
[D] Corvus
Show Answer
Correct Answer: C [Alcyonacea]
Notes:
The scientific name of sea fan is Alcyonacea. Alcyonacea are an order of corals that do not produce calcium carbonate skeltons. They are found throughout the oceans of the world.
17. rRNA is synthesized by which of the following?
[A] Nucleus
[B] Nucleolus
[C] Golgi body
[D] Cytoplasm
Show Answer
Correct Answer: B [Nucleolus]
Notes:
Molecules of rRNA are synthesized by the nucleolus in a specialized region of the cell nucleus, which appears as a dense region within the nucleus and contains genes encoding rRNA.
18. Which of the following is the function of contractile vacuole?
[A] To carry out pinocytosis
[B] To carry out metabolic process
[C] To pump excess water out of the cell
[D] To carry out phagocytosis
Show Answer
Correct Answer: C [To pump excess water out of the cell]
Notes:
Contractile vacuoles that regulate intracellular water balance by storing and expelling excess water from the cell.
19. How many amino acids are needed to make proteins?
[A] 19
[B] 20
[C] 21
[D] 22
Show Answer
Correct Answer: B [20]
Notes:
Amino acids combine to form protein. It requires 20 amino acids to make a protein in both plants and animals. Amino acids and protein are considered as the main body building blocks.
20. Which of the following bacteria spreads Plague?
[A] Salmonella
[B] Campylobacter
[C] E. coli & Shigella
[D] Yersinia pestis
Show Answer
Correct Answer: D [Yersinia pestis]
Notes:
Plague is a disease affecting humans and other mammals that is caused by the bacterium Yersinia pestis. Humans commonly get plague after being bitten by a rodent flea that carries the plague bacterium.
