Which of the following animal is unisexual ?

Question

Accepted Answer

Option 3, Cockroach, is the correct answer because cockroaches are unisexual animals. This means that individual cockroaches are either male or female, possessing distinct sexual organs. In cockroaches, reproduction involves the mating of a male and a female, where the male transfers sperm to the female, which then fertilizes the eggs internally. This distinct separation of sexes is characteristic of unisexual organisms.

Now, let's examine why the other options are incorrect:

1. **Tapeworm**: Tapeworms are not unisexual; they are hermaphroditic. This means that each individual tapeworm possesses both male and female reproductive organs. They can self-fertilize or cross-fertilize with another tapeworm, which is a typical trait of hermaphroditic organisms.

2. **Leech**: Leeches are also hermaphroditic. Each leech has both male and female reproductive organs, allowing them to engage in reciprocal fertilization with another leech. This dual reproductive capability disqualifies them from being classified as unisexual.

3. **Earthworm**: Earthworms, like leeches, are hermaphroditic. They have both male and female reproductive organs within the same individual. Earthworms typically mate by aligning their bodies and exchanging sperm, which is then used to fertilize their eggs. This hermaphroditic nature means they are not unisexual.

In conclusion, the cockroach is the only option among the given choices that is unisexual, with distinct male and female individuals, making Option 3 the correct answer.