Question

Gray crescent is the area

• A. At the point 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 1

The correct option is B Just opposite to the site of entry of sperm into ovum

Fertilization in the amphibian causes a shift of some of the cortical cytoplasm. These cytoplasmic movements can be easily recognised by the dark pigment granules in the egg cortex. As a result of this rearrangement, a crescent-shaped region of underlying lighter-coloured (gray) cytoplasm becomes evident directly opposite the point on the cell, where the sperm penetrated the egg. Thus, the correct answer is option B.