NEETZoologyStructural Organisation in Animals
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In cockroaches, males can be distinguished from females by the presence of short, threadlike anal styles. Reason (R): Anal styles are paired, jointed filamentous structures present on the 10th segment of male cockroaches. In the light of the above statements, choose the most appropriate answer from
Options
- A(A) is true but (R) is false
- BBoth (A) and (R) are true and (R) is the correct explanation of (A)
- CBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- D(A) is false but (R) is true
Correct answer
A. (A) is true but (R) is false
Step-by-step solution
Assertion (A) is true because male cockroaches bear a pair of short, threadlike anal styles which are absent in females, making it a key feature of sexual dimorphism. Reason (R) is false because anal styles are unjointed, threadlike structures found on the 9th sternum of males. The description of 'paired, jointed filamentous structures present on the 10th segment' actually refers to anal cerci, which are present in both sexes. Therefore, (A) is true but (R) is false. Answer: (A) is true but (R) is false