In the prothallus of a vascular cryptogam, the antherozoids and eggs mature at different times. As a result

Question

Accepted Answer

C. 1. Recall what a prothallus is.

A **prothallus** is the free-living gametophyte of vascular cryptogams (pteridophytes), which bears both antheridia (producing antherozoids) and archegonia (producing eggs).

2. Understand the significance of different maturation times.

When the antherozoids and eggs on the same prothallus mature at **different times**, it means the male and female gametes are not ready to fuse simultaneously within the same individual.

3. Determine the consequence of this timing difference.

Since the gametes are not available together, **self-fertilisation** (fusion of gametes from the same prothallus) is **prevented**, promoting cross-fertilisation with gametes from a different prothallus instead.

4. Eliminate the other options.

This timing difference does not cause **sterility** (option A), does not indicate **apomixis** (asexual seed formation without fertilisation, option B), and it does actually **affect** the fertilization dynamics rather than leaving it unchanged (option D).

Hence, the answer is **Option C**.