21.

Assertion : Persons suffering from haemophilia fail to produce blood clotting factor VIII.

Reason : Prothrombin producing platelets in such persons are found in very low concentration

• If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

• If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false

Assertion : Mitochondria and chloroplasts are semi-autonomous organelles.

Reason : They are formed by division of pre-existing organelles as well as contain DNA but lack protein synthesizing machinery.

• If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

• If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false

Assertion : The fungi are widespread in distribution and they even live on or inside other plants and animals.

Reason : Fungi are able to grow anywhere on land, water or on other organisms because they have a variety of pigments, including chlorophyll, carotenoids, fucooxanthin and phycoerythrin.

• If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

• If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false

Assertion : C₄ photosynthetic pathway is more efficient than the C₃ pathway.

Reason : Photorespiration is suppressed in C₄ plants.

• If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

• If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false

Assertion : The atmospheric concentration of CO₂ at which photosynthesis just compensates for respiration is referred to as CO₂ compensation point. 

Reason : The CO₂ compensation point is reached when the amount of CO₂ uptake is less than that generated through respiration because the level of CO, in the atmosphere is more than that required for achieving CO₂ compensation point.

• If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

• If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false

Assertion : The duck-billed Platypus and the spiny ant-eater, both are egg-laying animals yet they are grouped under mammals.

Reason : Both of them have seven cervical vertebrae and 12 pairs of cranial nerves.

• If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

• If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false

Given below is a pedigree chart showing the inheritance ofa certain sex-linked trait in humans

The trait traced in the above pedigree chart is

• dominant X- linked

• recessive X- linked

• dominant Y- linked

• recessive Y- linked

A cross section at the midpoint of the middle piece of a human sperm will show

• centriole, mitochondria and 9 + 2 arrangement of microtubules

• centriole and mitochondria

• mitochondria and 9 + 2 arrangement of microtubules

• 9 + 2 arrangement of microtubules only

Which one of the following is a correct statement?

• "Bt" in "Bt-cotton" indicates that it is a genetically modified organism produced through biotechnology

• Somatic hybridization involves fusion of two complete plant cells carrying desired genes.

• The anticoagulant hirudin is being produced from transgenic Brassica napus seeds.

• "Flavr Savr" variety of tomato has enhanced the production of ethylene which improves its taste.

An insect bite may result in inflammation of that spot. This is triggered by the alarm chemicals such as

• histamine and dopamine

• histamine and kinins

• interferons and opsonin

• interferons and histones