Fact 1: Secondary growth forms secondary vascular tissues and bark.

Fact 2: Trees have the ability to undergo secondary growth and produce a woody body.

Given the two facts above, answer the question "What forms secondary vascular tissues and bark?" with the following options: 
- bamboo
 - humans
 - trees
 - ferns
 - fish
 - phytoplankton
 - plants
 - oak


 

   trees      