11. Which of the following is the reason behind bleeding through nose in high mountain regions? (UPSC Prelims 1979).
[A] The pressure of the blood capillaries is higher than the outside pressure
[B] The pressure at high altitudes is greater than that in the plains
[C] The blood pressure increases at high altitudes
[D] The blood pressure decreases at high altitudes
Show Answer
Correct Answer: A [The pressure of the blood capillaries is higher than the outside pressure]
Notes:
As altitude increases, the availability of oxygen decreases, making the air thinner and drier. Dry climates can cause drying and cracking inside the nose, which can lead to a nosebleed. The climate inside nose gets drier. This makes the blood vessels exposed inside your nose more likely to burst there than at lower altitudes.
12. Seed germination takes place in which of the following layers of soil profile?
[A] Organic layer
[B] Surface/A layer
[C] B layer
[D] C layer
Show Answer
Correct Answer: B [Surface/A layer]
Notes:
Surface layer/ A layer which is rich in humus content is responsible for seed germination. Living organisms which aids the production (such as earthworms) also are present in this layer.
13. How may cultivated species contribute to food production globally?
[A] 200
[B] 400
[C] 1000
[D] 900
Show Answer
Correct Answer: A [200]
Notes:
According to FAO’s report “The State of the World’s Biodiversity for Food and Agriculture”, of more than 6,000 plant species cultivated for food production, fewer than 200 contribute significantly to food production globally, regionally or nationally. Only 9 plant species account for almost two-thirds of total crop production.
14. The theory of DNA structure and nature was propounded by __?
[A] Oswald Avery
[B] James Black
[C] Watson and Crick
[D] John Eccles
Show Answer
Correct Answer: C [Watson and Crick]
Notes:
Watson and Crick realized that DNA was made up of two chains of nucleotide pairs that encode the genetic information for all living things.
15. What type of embryo is most often used for viral assays?
[A] Mouse
[B] Rat
[C] Cat
[D] Chicken
Show Answer
Correct Answer: D [Chicken]
Notes:
Chicken is a type of embryo is most often used for viral assays.
16. Which one of the following plants has seeds but no flowers and fruits?
[A] Bryophytes
[B] Gymnosperms
[C] Mosses
[D] Pteridophytes
Show Answer
Correct Answer: B [Gymnosperms]
Notes:
Gymnosperms are a group of seed-producing plants. These include conifers, cycads, ginkgo and gnatophytes, which make up the clade gymnosperms. These living members are also known as acrogynosperms.
17. Which of the following may be most likely to be missing from a gram-positive bacterium?
[A] Penicillin-binding protein
[B] Peptidoglycan
[C] Lipopolysaccharide
[D] Phospholipid bilayer membrane
Show Answer
Correct Answer: C [Lipopolysaccharide]
Notes:
Gram-negative bacteria are surrounded by a thin peptidoglycan cell wall. It itself is surrounded by an outer membrane containing lipopolysaccharides.
18. What are the characteristics of Pteridophyta?
[A] They are cryptogams, seedless and vascular
[B] The plant body has true roots, stem and leaves
[C] Spores develop in sporangia
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Pteridophytes are considered the first plants to develop on land, they are cryptogams, seedless and vascular, the plant body has true roots, stems and leaves, spores develop into sporangia, sporangia in clusters on the sporophyll sex organs are multicellular.
19. What is the common name of pteridophytes?
[A] Ferns
[B] conifers
[C] flowering plant
[D] None of these
Show Answer
Correct Answer: A [Ferns]
Notes:
The common name of pteridophytes is Ferns. Ferns are vascular plants that differ from lycophytes in having true leaves that are often pinnate.
20. In ferns, the leaves during young conditions are called__?
[A] Scale leaf
[B] Sporophyll
[C] Circinate Ptyxis
[D] None of these
Show Answer
Correct Answer: C [Circinate Ptyxis ]
Notes:
In ferns, the leaves during young conditions are called Circinate Ptyxis.
