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. At which stage in its life-cycle does the silkworm yield the fibre of commerce? (UPSC Prelims 2000)
[A] Egg
[B] Larva
[C] Pupa
[D] Imago
Show Answer
Correct Answer: C [Pupa]
Notes:
Silk worm yield the fibre from pupa stage, which is commercially used to produce clothes.
13. Which among the following is an autotroph?
[A] Honey bee
[B] Algae
[C] Grasshopper
[D] Butterfly
Show Answer
Correct Answer: B [Algae]
Notes:
Autotrophs are the organisms which are able to prepare their own food without depending on other organism. Auto means self and prophs means food. All the organisms which are capable of carrying photosynthesis are examples of autotrophs.
14. Pollination by which among the following is called as ornithophily?
[A] Rodents
[B] Aquatic animals
[C] Ants
[D] Birds
Show Answer
Correct Answer: D [Birds]
Notes:
Ornithophily refers to the pollination assisted by the birds. Ornithology is a branch of science which studies about birds. Dr. Salim Ali is a famous Indian ornithologist.
15. Which of the following was invented by Jonas Salk?
[A] Polio Drop
[B] Polio Vaccine
[C] BCG Vaccine
[D] aspirin
Show Answer
Correct Answer: B [Polio Vaccine]
Notes:
The first effective polio vaccine was developed in 1952 by Jonas Salk. Polio, or poliomyelitis, is a disabling and life-threatening disease caused by the poliovirus.
16. How many of the following blood cells are there in the human body?
[A] 25 trillion
[B] 15 trillion
[C] 35 trillion
[D] 55 trillion
Show Answer
Correct Answer: A [25 trillion]
Notes:
Adult humans have an average of about 25 trillion RBCs in their bodies. Women usually have fewer RBCs than men
17. Which of the following is hemoglobin?
[A] Primary structure
[B] Secondary structure
[C] Tertiary structure
[D] Quaternary structure
Show Answer
Correct Answer: D [Quaternary structure]
Notes:
Hemoglobin has a quaternary structure. It consists of two pairs of separate proteins, designated α and β chains.
18. The cytoplasmic membrane of which of the following organisms contains sterols?
[A] Clostridum
[B] Proteus
[C] Mycoplasma
[D] Bacillius
Show Answer
Correct Answer: C [Mycoplasma]
Notes:
Mycoplasma is a genus of bacteria that do not have a cell wall surrounding the cell membrane.
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. 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.
