Fact 1: Plants use cellulose for their cell walls.

Fact 2: Vegetation includes shrubs and cactus plants.

Given the two facts above, answer the question "what uses cellulose for their cell walls?" with the following options: 
- cactus
 - Oak
 - Conifers
 - Trees
 - h2o
 - flowers
 - insects
 - humans


 

 cactus        