A sperm cell must move in order to reach the egg cell. An egg cell must divide into many separate sperm cells. An egg cell must move in order to reach the sperm cell. A sperm cell must combine with many different egg cells.
I gave my students this multiple choice question: Why is the structure of a sperm cell very different from the structure of an egg cell?

Only one answer is correct among these 4 choices:
- A sperm cell must move in order to reach the egg cell.
- An egg cell must divide into many separate sperm cells.
- An egg cell must move in order to reach the sperm cell.
- A sperm cell must combine with many different egg cells.

Could you tell me which one is correct?

A sperm cell must move in order to reach the egg cell.