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

Fact 2: Fertilization is complete when the sperm and egg nuclei fuse.

Given the two facts above, answer the question "Fertilization occurs when a sperm and nuclei what?" with the following options: 
- fuse
 - leave
 - CO 2
 - fusion
 - emerge
 - grow
 - H 2 O
 - procreate


 

 fuse        