1. Stapes, the smallest and the lightest bone in human body, is the part of which organ ?
[A] Ear
[B] Nose
[C] Neck
[D] hand
Show Answer
Correct Answer: A [Ear]
Notes:
An adult human has 206 bones while a new born baby has 300 bones. 94 bones fuse as a baby grows. The total number of bones in human skull is 29. The face of a man is made up of 14 bones. Largest and longest bone is femur (thigh bone).The shortest bone in the human body is stapes or stirrup bone in the middle ear.
2. Which among the following is found in a Bacteriophage?
[A] only RNA
[B] only DNA
[C] Both RNA & DNA
[D] Either RNA or DNA
Show Answer
Correct Answer: D [Either RNA or DNA]
Notes:
Either RNA or DNA is found in a Bacteriophage. A bacteriophage which is also informally known as a phage, is a virus that infects and replicates within bacteria and archaea.
3. Which of the following ecosystems showcases the highest biodiversity?
[A] Mangroves
[B] Deserts
[C] Coral Reefs
[D] Alpine Meadows
Show Answer
Correct Answer: C [Coral Reefs]
Notes:
The Coral Reef ecosystem showcases the highest biodiversity among the options provided. This is due to the ideal tropical environment in which they exist, offering a wide range of habitats, shelter, and nourishment for an astonishing array of marine life. In terms of biodiversity, they are second only to tropical rainforests. Interestingly, despite covering less than 1% of the ocean floor, coral reefs support about 25% of all known marine species.
4. With reference to classification of the flora and fauna, the meaning of term “Taxon” is __?
[A] A group of same species
[B] A group of organisms with same chromosome number
[C] A group of category of organisms
[D] A group of same genera
Show Answer
Correct Answer: C [ A group of category of organisms]
Notes:
In biology, a taxon (plural taxa; back-formation from taxonomy) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit.
5. Aves have evolved from which of the following?
[A] Amphibians
[B] Arthropods
[C] Mammals
[D] Reptiles
Show Answer
Correct Answer: D [Reptiles]
Notes:
Birds evolved from theropod dinosaurs during the Jurassic around 165–150 million years ago. Birds aren’t just closely related to dinosaurs, they really are dinosaurs! This is what most people mean when they say that birds are reptiles, although technically according to the phylogenetic system mammals are also reptiles.
6. Who among the following has given the theory of evolution of species by natural selection?
[A] Mendel
[B] Darwin
[C] Dalton
[D] Morgan
Show Answer
Correct Answer: B [Darwin]
Notes:
Charles Robert Darwin gave the theory of evolution in his book “The Origin of Species”. The theory proposed by him is known as “The Theory of Natural Selection”.
7. Which of the following at the opposite of micropylar end represents the basal part of the ovule?
[A] Hilum
[B] Nucellus
[C] Chalaza
[D] Funicle
Show Answer
Correct Answer: C [Chalaza]
Notes:
The chalaza is a structure inside bird and reptile eggs and plant ovules. It attaches or suspends the yolk or nucellus within the larger structure. It represents the basal part of the ovule.
8. 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.
9. Guinea pigs used in medical research belong to which of the following categories? (UPSC Prelims 1989)
[A] Rodents
[B] Black swine
[C] Stocky and brown in colour
[D] Found in Asia only
Show Answer
Correct Answer: A [Rodents]
Notes:
The guinea pig or domestic guinea pig also known as cavy or domestic cavy, is a species of rodent belonging to the family Caviidae and the genus Cavia.
10. Fat present below the skin surface in our body, acts as a barrier against which of the following losses? (UPSC Prelims 1996)
[A] Loss of heat from the body
[B] loss of essential body fluids
[C] loss of salts from the body
[D] entry of harmful micro-organisms from the environment
Show Answer
Correct Answer: A [Loss of heat from the body]
Notes:
Adipose tissue that’s fat cells which are under the skin act as barrier to loss of the heat from the body and it protects the skin from entering of highly reactive UV rays of the sun. Fat present below the skin surface in our body, act as an insulator against loss of heat from the body. The deposited fat works as barrier, which prevents loss of heat.
