Breakdown of detritus into smaller particles by earthworm is a process called

Given below are two statements:
Statement $I:$
Decomposition is a process in which the detritus is degraded into simpler substances by microbes.
Statement $II:$
Decomposition is faster if the detritus is rich in lignin and chitin.
In the light of the above statements,choose the correct answer from the options given below:

Select the incorrect statement regarding the process of decomposition.

The rate of decomposition is controlled by .........

If all decomposers are removed from an ecosystem,what will happen?

The decomposition of organic compounds in the presence of $O_2$ without the development of odoriferous substances is known as: