11. Xylem helps in transportation of which of the following?
[A] Food
[B] Water
[C] Both food and water
[D] Nutrients
Show Answer
Correct Answer: B [Water]
Notes:
Xylem is a type of tissue in vascular plants that transports water and some nutrients from the roots to the leaves. Water is passively transported into the roots and then into the xylem. The forces of cohesion and adhesion cause the water molecules to form a column in the xylem.
12. Which of the following is responsible for giving colour to human skin?
[A] Haemoglobin
[B] Melanin
[C] Luciferin
[D] Flavonoids
Show Answer
Correct Answer: B [Melanin]
Notes:
Melanin is a pigment that gives human skin, hair, and eyes their color. Dark-skinned people have more melanin in their skin than light-skinned people have. Melanin is produced by cells called melanocytes.
13. Through which of the following mechanisms genes control the activity of living organisms? (UPSC Prelims 1986)
[A] Photosynthesis
[B] Protein synthesis
[C] Vitamins
[D] Hormones
Show Answer
Correct Answer: B [Protein synthesis]
Notes:
The genes control the characteristic by making a specific protein. Genes are the segment of DNA that contains information to form RNA which ultimately forms protein. Each gene contains two alleles and this instructs the cell to make protein for expression of traits.
If the plant has gene for green seeds then it will make protein which will give green colour to seeds.
14. The introduction of Pre-natal Diagnostic Techniques Bill in Parliament was prompted by the increasing incidence of? (UPSC Prelims 1992)
[A] Female foeticide
[B] Failure of contraceptive devices
[C] Spurious drugs being used for prenatal immunisation
[D] Unqualified persons diagnosing pregnancy in villages by primitive methods
Show Answer
Correct Answer: A [Female foeticide]
Notes:
The introduction of Pre-natal Diagnostic Techniques Bill in Parliament was prompted by the increasing incidence of Female foeticide. Female feticide is the abortion of a female foetus outside of legal methods. The frequency of female foeticide in India is increasing day by day. The natural sex ratio is assumed to be between 103 and 107, and any number above it is considered as suggestive of female foeticide.
15.
Who among the following is considered to be the father of Comparative Anatomy?
[A] Georges Cuvier
[B] Stephen Hales
[C] Hugo de Vries
[D] Edwin John Butler
Show Answer
Correct Answer: A [Georges Cuvier]
Notes:
Georges Cuvier is considered to be the father of Comparative Anatomy.
16. Which of the following does not have a complete cell wall?
[A] blue-green algae
[B] Saccharomyces
[C] sea fan
[D] cyanobacteria
Show Answer
Correct Answer: C [sea fan]
Notes:
Sea fan does not have a complete cell wall. The sea fan is an animal belonging to the phylum Coelenterata. Not all animals have a cell wall.
17. What is an evolutionary important character of Selaginella?
[A] Strobili
[B] Rhizophore
[C] Heterosporous nature
[D] Ligule
Show Answer
Correct Answer: C [Heterosporous nature]
Notes:
The evolutionary important character of Selaginella is the heterogametic nature. Selaginella produces two types of spores, microspores and megaspores and in heterospory, the life cycle of Selaginella leads to seed habit formation.
18. In pteridophytes, which of the following is the dominant generation?
[A] gametophytic
[B] haploid
[C] diploid
[D] triploid
Show Answer
Correct Answer: C [diploid]
Notes:
In pteridophytes, the dominant is the diploid sporophytic generation because it develops from the diploid zygote.
19. The resin duct of a gymnospermous stem is an example of__?
[A] Big vacuole
[B] Lysigenous cavity
[C] Intercellular space
[D] Schizogenous cavity
Show Answer
Correct Answer: D [Schizogenous cavity]
Notes:
Schizogenous cavities are formed by the separation of glandular cell initials, resulting in a space lined by secretory epithelial cells.
20. In gymnosperms how many male gametes are produced by each pollen grain?
[A] 4
[B] 3
[C] 2
[D] 1
Show Answer
Correct Answer: C [2]
Notes:
In gymnosperms, there are only 2 male gametes are produced by each pollen grain.
