If sperm swim to an egg, forming a zygote inside an archegonium, then where is a zygote formed by sperm swimming to an egg?

Answer choices:
- colder and wetter
 - ocean water
 - graptolites
 - rapid expansion
 - a delta
 - an archegonium
 - barnacles
 - an organism's body

 

      an archegonium    