Above the layer of gravel, a layer of _____ is present.

Choose the correct word from the box and fill in the blank:

(subsoil, gravel, rocks, loam, crops)

Soil is formed by the breaking down of _____ into smaller pieces.

Choose the right word and fill in the blank:

Tiny pieces of rocks form _____. (water/soil) 

Choose the right word and fill in the blank provided below.

When we throw garbage carelessly it leads to _____ (land/air) pollution.