Protocooperation is seen in

Options

A. Birds and cattles or crocodiles
B. ox pecker or tick birds and rhinoceros
C. shrimps and fish of coral reefs
D. all of these

Answer

### Step-by-Step Solution:

1. **Understanding Protocooperation**:
- Protocooperation is a type of interaction between two different species where both organisms benefit from the relationship.

2. **Characteristics of Protocooperation**:
- It is a non-obligatory interaction, meaning that while both species benefit from each other, they can survive independently if needed.
- The relationship is mutually beneficial, meaning both organisms gain something valuable from the interaction.

3. **Examples of Protocooperation**:
- **Oxpecker and Crocodile**: The Oxpecker bird feeds on parasites found on the skin of the crocodile. In return, the crocodile gets rid of these harmful parasites.
- **Birds and Cattle**: Similar to the Oxpecker and crocodile relationship, certain birds feed on insects and parasites found on cattle, providing the cattle with protection from these pests.
- **Shrimps and Fish in Coral Reefs**: Shrimps feed on dead skin and parasites found on fish. In return, the fish benefit from the removal of these harmful organisms.

4. **Conclusion**:
- Based on the examples provided, protocooperation can be seen in various interactions among different species, including oxpeckers and crocodiles, birds and cattle, as well as shrimps and fish. Therefore, the correct answer to the question is "all of these".