Grey crescent is the area

Options

A. At the point of entry of sperm into ovum
B. Just opposite to the site of entry of sperm into ovum
C. At the animal pole
D. At the vegetal pole

Answer

### Step-by-Step Solution:

1. **Understanding the Frog Egg Structure**:
- The frog egg has two distinct poles: the animal pole and the vegetal pole.
- The animal pole is where the embryo will develop, while the vegetal pole contains the yolk, which provides nutrients.

2. **Identifying the Vitelline Membrane**:
- The vitelline membrane surrounds the egg and separates the cytoplasm from the external environment.
- Below this membrane is the yolk, which is yellow in color.

3. **Cytoplasm Function**:
- The cytoplasm is present above the yolk and plays a crucial role in absorbing heat and providing a medium for cellular processes.
- It contains melanin granules that help in heat absorption.

4. **Defining the Gray Crescent**:
- The gray crescent is a specific area in the frog egg that is formed as a result of the distribution of dense cytoplasm.
- It appears opposite to the point where the sperm enters the egg.

5. **Significance of the Gray Crescent**:
- The gray crescent is important for the process of fertilization.
- It is formed to facilitate the proper development of the embryo after fertilization.

6. **Conclusion**:
- The gray crescent is located just opposite to the site of sperm entry into the egg, and it consists of dense cytoplasm that plays a vital role in embryonic development.