To determine which of the following animals is bisexual, we need to understand the term "bisexual" in the context of reproduction. Bisexual organisms, also known as hermaphrodites, possess both male and female reproductive organs and can produce both male and female gametes.
### Step-by-Step Solution:
1. **Understanding Bisexuality**:
- The term "bisexual" can be broken down into "bi" meaning two, and "sexual" referring to reproductive organs. Bisexual organisms have both male and female reproductive organs.
2. **Analyzing the Options**:
- The options provided are ants, cockroaches, leeches, and wasps.
- Ants, cockroaches, and wasps belong to the phylum Arthropoda, which typically exhibit sexual dimorphism, meaning they have separate male and female individuals.
3. **Characteristics of Arthropods**:
- In Arthropods (like ants, cockroaches, and wasps), individuals are unisexual, meaning they possess either male or female reproductive organs, but not both.
4. **Identifying the Correct Option**:
- Leeches belong to the phylum Annelida, which is known for having hermaphroditic organisms. This means leeches possess both male and female reproductive organs within the same individual.
5. **Specifics about Leeches**:
- The scientific name for the common leech is Hirudo medicinalis. Leeches are protandrous, meaning that the male reproductive organs develop before the female reproductive organs. This allows for mutual fertilization when two leeches mate.
6. **Conclusion**:
- Based on the analysis, the only bisexual organism among the options is the leech.
### Final Answer:
**Leech** is the bisexual organism.
