Question

Assertion :Of all the leucocytes only neutrophils are chemotaxic. Reason: WBCs are chemotaxic as they have to locate and synthesize the antibodies.

• 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. Both Assertion and Reason are incorrect.

Answer 1

The correct option is D Both Assertion and Reason are incorrect.

Not only neutrophils but also monocytes (which later changes into macrophages) are chemotaxis. They can squeeze through openings in blood vessels by a process called as diapedesis. They move around using amoeboid motion. They are attracted to certain chemicals produced by the immune system or by bacteria and migrate toward areas of higher concentrations of these chemicals (chemo-taxis). Thus, assertion is wrong.
Both the WBC i.e., neutrophils and monocytes kill bacteria by a process called phagocytosis. They do not produce antibodies. Thus, the reason is also wrong.

Therefore, the correct answer is option D.