Passage Summary: All higher animals need eggs to reproduce, but some don't need sperm. One type of salamander is entirely female and clones itself, which makes the species less able to adapt than species that have both males and females.

Reasoning: Reproduction in higher animals requires eggs but not always sperm; some all-female species clone themselves, which results in lower adaptability compared to species with two sexes.

Analysis: In a 'Must be False' question, we treat the stimulus as a set of absolute rules and look for an answer choice that contradicts them. The text establishes that while eggs are a universal requirement for higher animal reproduction, sperm is optional. It also notes that female-only species are less adaptive than mixed-sex ones. Look for an answer that claims a higher animal can reproduce without eggs or suggests that a single-sex species is more adaptive than a dual-sex one.