Fact 1: Fertilization occurs when a sperm and an egg fuse.

Fact 2: Fertilization As far as fertilization, timing is critical.

Given the two facts above, answer the question "timing is critical for what occurs when a what and an egg fuse?" with the following options: 
- Cooking
 - Flowers
 - fusion
 - embryos
 - pollen
 - seeds
 - heat
 - sperm


 

        sperm 