Fact 1: Moss causes chemical weathering.

Fact 2: Mosses lack the roots and stems that other plants have.

Given the two facts above, answer the question "Plants lacking roots and stems cause what?" with the following options: 
- cause their death
 - harmful substances
 - Greenhouse gases
 - dry conditions
 - chemical weathering
 - Damages them
 - deforestation
 - Dehydration


 

     chemical weathering    