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

Fact 2: When a sperm cell fertilizes an egg cell, a fertilized egg or zygote is formed.

Given the two facts above, answer the question "Where is a zygote formed by sperm swimming to an egg?" with the following options: 
- colder and wetter
 - ocean water
 - graptolites
 - rapid expansion
 - a delta
 - an archegonium
 - barnacles
 - an organism's body


 

      an archegonium   