Answer:
The correct answer is - They secrete acid that breaks away rocks
Step-by-step explanation:
Lichen causes chemical weathering to break the rocks quickly which is the excretion of various acids like oxalic acid and many more organic acids that can cause a significant impact on the rock by dissolving minerals.
By breaking the rocks it forms the ground for the plant that will come later in place of the bare rocks by this chemical weathering process. An example of chemical weather is a change of the granite to clay with the help of hydrolysis.