Question

gaseous fuel formed by decomposing organic waste such as farm waste animal and human waste ......................​

Answer 1

The biogas
Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. Biogas is a renewable energy source. Biogas is a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen.

Answer 2

it's called biogas.
biogas is formed by decomposing organic waste such as plants, animals and humans wastes.