the sex of the egg the age of the egg the size of the egg the genes of the egg
I gave my students this multiple choice question: Which of these determines whether a fertilized egg develops into a toad, a snake, or a lizard?

Only one answer is correct among these 4 choices:
- the sex of the egg
- the age of the egg
- the size of the egg
- the genes of the egg

Could you tell me which one is correct?

the genes of the egg