This sentence is grammatically incorrect.
It should be ...............most of the work of mixing humus with ........................
If that is the right sentence then what it says is true.
yes it is true they even make up most of the soil by their droppings'
true
No, they do not. Plants contribute most of the organic remains that form humus.
Organic remains comes from animals, foods, etc. Those are examples of Organic remains. So the answer is yes they come from organic things.
Organic Sedimentary Rocks are formed from remains of plants and animals.
coal
Dead and decayed remains of plants and animals, called Humus.
organic sedimentary
It is called humus.
It is called humus.humus
It is called humus.humus
Organic Remains are remains from a living thing such as dead leaves or a dead tree. The Organic Remains are no longer in use but they have to be from something in nature.
This organic material is made up of living organisms such as plants and animals, dead plants and animals, and nutrients that have come from decomposed plants and animals.
The type of rock that forms where the remains of plants and animals are deposited in thick layers are called organic sedimentary rock.