Question

ASSERTION: Blood of insects is colorless.
REASON: The blood of insects does not play any role in transport of oxygen.
A) Both assertion and reason are correct and reason is the correct explanation for assertion.
B) Both assertion and reason are correct but reason is not the correct explanation for assertion.
C) Assertion is correct but reason is incorrect.
D) Assertion is incorrect but reason is correct.

Answer 1

Hint: The blood of the insect is known as hemolymph and it is colorless because hemoglobin is not present in its blood. The circulatory system of insects is of open type i.e., it has no veins and arteries. The oxygen is directly transferred into the tissue through the tracheoles.

Complete answer:
Option (A): Both assertion and reason are correct but the reason is not the correct explanation for assertion because the blood of insects is colorless due to the absence of hemoglobin.
Option (B): The blood of insects is colorless due to the absence of hemoglobin. Also, the blood of an insect does not play any role in the transport of oxygen because the transport of oxygen requires the attachment of oxygen molecules to the hemoglobin. As an insect’s blood does not consist of hemoglobin therefore its blood has no role in the transport of oxygen. The transport of oxygen in insects occurs via tracheoles i.e., an elaborate system of tubes and air sacs. So, both the assertion and the reason are correct, but the reason for the assertion is not the correct explanation.
Option (C): The assertion i.e., the blood of insects is colorless is correct and the reason i.e., the blood of insects does not play any role in the transport of oxygen is correct. In insects, the oxygen is transported via an elaborate system of tubes and air sacs but not by the blood.
Option (D): The assertion i.e., The blood of insects is colorless is correct because the blood of insects lacks a red-colored pigment called hemoglobin and the reason is also correct.

Hence, the correct option is (B).

Note: Animal blood is red colored due to the presence of hemoglobin and is known for transporting oxygen while the blood of the insect is colorless due to the absence of hemoglobin and the oxygen transport takes place via tracheoles but not by the circulatory system of the insect.