Fact 1: Plants release oxygen during the day but not during the night.

Fact 2: Ferns are seedless vascular plants.

Given the two facts above, answer the question "What releases oxygen during the day but not during the night?" with the following options: 
- humans
 - Trees
 - dogs
 - cacti
 - cats
 - Oak
 - ferns
 - apples


 

       ferns  