Q.Which of the following is hermaphrodite?

Hermaphroditism

Most animals we know are either male or female. But a surprising number of animals carry both male and female reproductive organs in the same body. This condition is called hermaphroditism, and such an animal is a hermaphrodite (also described as bisexual or monoecious in some texts).

What it means

A hermaphrodite produces both eggs (female gametes) and sperm (male gametes) because it has both sets of reproductive organs — ovaries/testes together in one individual. This is common in many invertebrates, particularly those that are slow-moving or parasitic.

Why it can be an advantage

Consider an animal that lives buried in soil, or lives inside a host as a parasite — it may rarely meet a partner. Being a hermaphrodite is a great advantage here:

• Any two individuals that meet can mate, since every one has both sexes (no need to find a specific male or female).
• In some cases the animal can even self-fertilise if no partner is available, guaranteeing reproduction.

This is why hermaphroditism is especially common among parasites and sedentary animals, where finding a mate is difficult.

Classic examples

• Earthworm — a well-known hermaphrodite; each worm has both testes and ovaries. However, it usually undergoes cross-fertilisation (two worms exchange sperm) rather than fertilising itself, which keeps genetic variation.
• Tapeworm — a parasitic flatworm living inside the host's gut, hermaphrodite, which helps it reproduce even when alone.
• Leech — also a hermaphrodite. …