Quiz 237 – UPSC Previous Year’s Biology Questions with Explained Answers

In the context of organic evolution, the loss of limbs in snakes is explained by the phenomenon of:

(a) use and disuse of organs

(b) adaptation to living in burrows

(c) natural selection

(d) inheritance of acquired characters

Explanation:

In the context of organic evolution, the loss of limbs in snakes is explained by the phenonmenon of use and disuse of organs.

Ans- (a)


 

The cellular and molecular control of programmed cell death is known as:

(a) apoptosis

(b) ageing

(c) degeneration

(d) necrosis

Explanation:

The cellular and molecular control of programmed cell death is known as apoptosis.

Ans- (a)


 

Assertion (A) : Drinking of whisky increases the frequency of urination.

Reason (R): Alcohol intake speeds up the secretion of vasopressin in the body.

(a) Both A and R are true and R is the correct explanation of A.

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false

(d) A is false but R is true.

Explanation:

Both Assertion and Reason are correct and R explains A correctly. Alcohol intake speeds up the secretion of vasopressin in the body.

Ans- (a)


 

Foot and mouth disease in animals, a current epidemic in some parts of the wolrd, is caused by:

(a) bacterium

(b) fungus

(c) protozoan

(d) virus

Explanation:

Foot and mouth disease in animals is caused by the virus. These viruses are of seven kinds – O, A, C, Asia-I, SAT -1, Sat-2 and SAT-3.

Ans- (a)


 

Which one of the following is monogamous?

(a) Wolf

(b) Walrus

(c) Seal

(d) Deer

Explanation:

Deer is monogamous.

Ans- (d)


 

Consider the following statements:

  1. Dengue is a protozon disease transmitted by mosquitoes.
  2. Retro-orbital pain is not a symptom of dengue.
  3. Skin rash and bleeding from nose and gums are some of the symptoms of dengue.

Which of the statements given above is/are correct?

(a) 1 and 2

(b) 3 only

(c) 2 only

(d) 1 and 3

Explanation:

Dengue is a viral disease. It is characterized by fever, severe muscle and joint pain and rash.

Ans- (b)


 

Assertion (A): The person with diabetes insipidus feels thirsty.

Reason (R): A person with diabetes insipidus suffers from excess secretion of vasopressin.

(a) Both A and R are true and R is the correct explanation of A.

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false

(d) A is false but R is true.

Explanation:                

Vasopressin or antidiuretic hormone is secreted by posterior pituitary gland. The deficiency of vasopressin results in a disorder known as diabetes insipedus. The main symptoms of diabetes inspedus are increase in thrust and increase in urination. So, the assertion is true but reason is false.

Ans- (c)


 

With reference to normal human beings, consider the following statements:

  1. In response to the presence of HCI, secretin is produced from the duodenum.
  2. Enterogastrone is produced in the small intenstine in response to the presence of fatty acids.

Which of the statements is/are correct?

(a) only 1

(b) only 2

(c) Both 1 and 2

(d) Neither 1 nor 2

Explanation:

The medium of digestion in stomach is acidic due to presence of HCI. When the food enters in duodenum (small intestine), secretion is produced by intestine that stimulated pancreas for pancreatic juice secretion.

Ans- (c)


 

Assertion (A): Unsaturated fats are more reactive compared with the saturated fats.

Reason (R): Unsaturated fats have only single bonds in their structure.

(a) Both A and R are true and R is the correct explanation of A.

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false

(d) A is false but R is true.

Explanation:     

Assertion is true but R is not correct. Compound having double bond in their structure are more unstable compound in comparison to single bond holder compounds. Unsaturated fats those have double bounds in their structures are more reactive than saturated fats.

Ans- (c)


 

Assertion (A): Scientists can cut apart and paste together DNA molecules at will, regardless of the source of the molecules.

Reason (R): DNA fragments can be manipulated using restriction endonucleases and DNA ligases.

(a) Both A and R are true and R is the correct explanation of A.

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false

(d) A is false but R is true.

Explanation:     

Restriction endonucleases and DNA ligases are used in recombinant DNA technology and DNA ligases. So, Both Assertion and Reason is True.

Ans- (a)

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Quiz 234 – UPSC Previous Year’s Chemistry Questions

Quiz 223 – UPSC Previous Year’s Biology Questions with Explained Answers

Quiz 226 – UPSC Previous Year’s History Questions with Explained Answers

Quiz 203 – Science Previous Year’s Question Paper

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