Whats the rest of the question?
The answer to this question is "The New Kingdom"
Answer: The following are needed for the soil to be fertile 1) Sand 2) Clay 3) humus 4) Useful minerals.
Of a truth the decomposition is nutritious but aeration amongst other factors are important.
Explanation: The soil is a world for living things so without these buddies we can't say its very fertile.
I think what the author means is Friends, like bring yor friends along.
