Question

what will happen if decomposers will not be there?

Answer 1

If there would be no decomposers
the waste on earth would increase for sure which would lead to the imbalance in the environment as the last member of all of the food webs and cycles would not be present their to mess it up for whole

Answer 2

the decomposers Perform a very crucial function. in their absence all the dead trees and animal remaining the same as they are and our earth will filled with dead bodies