Fact 1: Fertilization occurs when sperm swim to an egg inside an archegonium.

Fact 2: If fertilized, the egg implants itself in the uterus.

Given the two facts above, answer the question "the egg implants itself in the uterus after sperm does what?" with the following options: 
- permineralization
 - release more eggs
 - rapid expansion
 - migrate
 - swim to the sea
 - reproduce
 - swim to an egg
 - drown in the uterus


 

       swim to an egg  