Fact 1: Roots have primary and secondary meristems for growth in length and width.

Fact 2: Size is measured by width and length.

Given the two facts above, answer the question "growth in what is caused by primary and secondary meristems in roots?" with the following options: 
- H 2 O
 - bamboo
 - population
 - offspring
 - bushes
 - bulbs
 - clouds
 - size


 

        size 