11. 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.
12. Which of the following classes belongs to an Octopus? (UPSC Prelims 2003)
[A] an arthropod
[B] an echinoderm
[C] a heimchordate
[D] a mollusc
Show Answer
Correct Answer: D [a mollusc]
Notes:
The octopus is a soft-bodied, eight-limbed mollusc of the order Octopoda. Around 300 species are recognised, and the order is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids.
13. Which among the following is the smallest endocrine gland in the human body?
[A] Pineal gland
[B] Pancreas
[C] Hypothalamus
[D] Liver
Show Answer
Correct Answer: A [Pineal gland]
Notes:
Pineal gland which is located in brain’s midline is the smallest of all the endocrine glands. Melatonin harmone is secreted by the pineal gland.
14. Which of the following is the taxonomic family of humans?
[A] Hominidae
[B] Haplorhini
[C] Primates
[D] Homini
Show Answer
Correct Answer: A [Hominidae]
Notes:
The genus of the human being today is called Homo and the man today is called as Homo sapiens. From simple life forms that were unicellular to the development of multicellular organisms gave rise to the vertebrates. The family to which human beings belong is called Hominidae. It was in the Miocene age that the family Hominidae split from the Pongidae(apes) family.
15. Which among the following genus is known as the ‘handy man’?
[A] Homo sapiens sapiens
[B] Homo habilis
[C] Homo sapiens neanderthelensis
[D] Homo erectus
Show Answer
Correct Answer: B [Homo habilis]
Notes:
Homo habilis– He had a face similar to his ancestors. The skull and brain size indicate that he may have been able to speak. The earliest tools made were from this era. Homo habilis is known as the ‘handy man’ because he was the first to make and use tools.
16. Which of the following statements are correct with respect to homeostasis?
1. Ecosystems are capable of maintaining their state of equilibrium.
2. They cannot regulate their own species structure and functional processes.
Select the correct option from the codes given below:
[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 & 2
Show Answer
Correct Answer: A [Only 1]
Notes:
Ecosystems are capable of maintaining their own state of equilibrium. They can regulate their own species structure and functional processes. This capacity of ecosystem of self regulation is referred to as homeostasis.
17. Who among the following discovered the cell wall?
[A] Robert Hooke
[B] Boveri
[C] J Rhodin
[D] Van Beneden
Show Answer
Correct Answer: A [Robert Hooke]
Notes:
A plant cell wall was first observed and named by Robert Hooke in 1665.
18. What kind of sugar is present in sugarcane?
[A] Sucrose
[B] Hexose
[C] Glucose
[D] Ribose
Show Answer
Correct Answer: A [Sucrose]
Notes:
Sucrose is present in sugarcane. It is also known as cane sugar or table sugar. It is the combination of glucose and fructose.
19. Which of the following virus has its envelope from the host cell nucleus?
[A] Paramyxoviruses
[B] Retroviruses
[C] Orthomyxoviruses
[D] Herpesviruses
Show Answer
Correct Answer: D [Herpesviruses]
Notes:
The Herpesviridae are a large family of DNA viruses. It causes infections and some diseases in animals, including humans. Herpes viruses are divided into three groups: α herpesviruses, herpes simplex virus types 1 and 2.
20. Viral DNA is removed from the host’s chromosomes and the lytic cycle is called which of the following process?
[A] spontaneous induction
[B] inductive infection
[C] resultant induction
[D] spontaneous infection
Show Answer
Correct Answer: A [spontaneous induction]
Notes:
Viral DNA is removed from the host’s chromosomes and the lytic cycle is called spontaneous induction.
