11. Which one of the following is useful for biological control of pests? (UPSC Prelims 1991)
[A] Honey bees and locusts
[B] Scorpions and spiders
[C] Wasps and birds
[D] Parrots and kites
Show Answer
Correct Answer: B [Scorpions and spiders]
Notes:
Spiders, mites, scorpions, and several related groups are not insects, but belong to the arthropod class Arachnida. About 15 families of spiders are frequently encountered in crops, where they provide benefit as natural control agents.
12. Which among the following is the name given to the ductless and secretory glands in the human body? (UPSC Prelims 1997)
[A] Endocrine glands
[B] Exocrine glands
[C] Salivary glands
[D] None of the above
Show Answer
Correct Answer: A [Endocrine glands]
Notes:
Ductless glands which are also known as internally secreting glands or endocrine glands secrete their products or hormones directly into the blood stream in response to instructions from the brain.
13. Which of the following correctly defines an Antigen? (UPSC Prelims 2002)
[A] Lowers body temperature
[B] destroys harmful bacteria
[C] triggers the immune system
[D] is used as an antidote to poison
Show Answer
Correct Answer: C [triggers the immune system]
Notes:
An antigen is any substance that causes your immune system to produce antibodies against it. An antigen may be a substance from the environment, such as chemicals, bacteria, viruses, or pollen. An antigen may also form inside the body.
14. Who gave theory of photosynthesis?
[A] Maurice Hilleman
[B] Jack Horner
[C] Jan Ingenhousz
[D] Franz Mesmer
Show Answer
Correct Answer: C [Jan Ingenhousz]
Notes:
Jan Ingenhausen is a Dutch-born British physician and scientist, best known for his discovery of the process of photosynthesis, by which green plants absorb carbon dioxide and release oxygen in sunlight.
15. Whooping cough is caused by which of the following?
[A] Bordetella pertussis
[B] Helicobacter pylori
[C] Yersinia pestis
[D] Treponema pallidum
Show Answer
Correct Answer: A [Bordetella pertussis]
Notes:
Pertussis is a respiratory disease commonly known as whooping cough. It is a very contagious disease caused by a type of bacteria called Bordetella pertussis.
16. Which of the following is not an auxiliary pigment?
[A] Chlorophyll ‘a’
[B] Chlorophyll ‘e’
[C] Phycocyanin
[D] Xanthophyll
Show Answer
Correct Answer: A [Chlorophyll ‘a’]
Notes:
Chlorophyll ‘a’ is an essential pigment, it is not helpful.
17. Which of the following is least likely to be found along the beach?
[A] Brown algae
[B] Red algae
[C] Mosses
[D] All the above
Show Answer
Correct Answer: C [Mosses]
Notes:
Mosses usually form dense green clumps or mats, often found in moist or shady places.
18. Which of the following also play a role in protecting plants against bacterial and fungal infections?
[A] Jasmonates
[B] Oligosaccharins
[C] Strigolactones
[D] Brassinosteroids
Show Answer
Correct Answer: B [Oligosaccharins]
Notes:
Oligosaccharides also play a role in protecting plants against bacterial and fungal infections. They act locally at the site of injury. They can also be carried to other tissues.
19. Which of the following is not a type of fertilization?
[A] Porogamy
[B] Chalazogamy
[C] Mesogamy
[D] Gynogamy
Show Answer
Correct Answer: D [Gynogamy]
Notes:
Fertilization is a process of sexual reproduction, which is followed by pollination and germination. Porogamy, Chalazogamy, and Mesogamy are types of fertilization.
20. Which of the following is an example of a plant with a Fibrous Root System?
[A] Carrot
[B] Onion
[C] Oak Tree
[D] Turnip
Show Answer
Correct Answer: B [Onion]
Notes:
A fibrous root system is characteristic of grasses and other monocotyledons like onions. Unlike in the taproot system of dicotyledonous plants where one major root originates from the stem and smaller roots arise off of this taproot, in a fibrous root system many equally sized roots arise off of the stem. These types of roots cover a larger surface area and are therefore better at absorbing nutrients and water from the soil.
