The loose upper layer that covers the Earth's crust is called ....................... .

The soil is composed of ........................ .

The main benefits of soil organisms are .............................. .

All the following are benefits of roots of plants to soil except ......................... .

....................... are the soil layers that lie beneath the top soil layers.

.................... dig tunnels in the soil to make nests.

Soil is a thin non-compacted superficial layer which covers the Earth's crust.

The texture of soil helps scientists to identify the metals inside it.

Humus is a dark material.

When a flower and some worms die, their bodies decay forming humus.

Humus adds nutrients to soil.

Minerals are resulted from breaking down rocks,

Animals need soil, because they eat plants that previously depend on soil.

Heat, winds, rains and running water break the rocks and convert them into small particles.

Soil is composed of two layers only.

The tunnels formed by earthworms and ants allow air, water and plant roots to pass easily through soil.