Cleavage in ctenophores is

Options

A. (a) equal
B. (b) radial
C. (c) incomplete
D. (d) determinate

Answer

To answer the question regarding cleavage in ctenophores, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ctenophores**:
- Ctenophores, also known as comb jellies, are a group of marine invertebrates that belong to the phylum Ctenophora. They are distinct from cnidarians, although they share some similarities.

2. **Cleavage Types**:
- Cleavage refers to the series of cell divisions that occur after fertilization. There are different types of cleavage patterns, including equal, unequal, radial, spiral, determinate, and indeterminate.

3. **Identifying the Correct Cleavage Type**:
- In ctenophores, the cleavage is typically described as **radial** and **determinate**. This means that the cleavage planes are symmetrical and the fate of the cells is determined early in development.

4. **Evaluating the Options**:
- The options provided are:
A. Equal
B. Radial
C. Incomplete
D. Determinate
- Since ctenophores exhibit radial cleavage and the cleavage is determinate, we need to analyze the options:
- A. Equal - This is incorrect as ctenophores do not have equal cleavage.
- B. Radial - This is partially correct, but it does not capture the determinate nature.
- C. Incomplete - This is incorrect as ctenophores do not have incomplete cleavage.
- D. Determinate - This is the correct answer as it encompasses the nature of cleavage in ctenophores.

5. **Final Answer**:
- The correct answer is **D. Determinate**.