Name the four sphere of the earth. why is land the most important natural resource for human being? define soil and what are it's three components? define humus. how is soil formed? describe the causes of unequal distribution of population on the land surface of the earth.

1) Everything in Earth's system can be placed into one of four major subsystems: land, water, living things, or air. These four subsystems are called “spheres.” Specifically, they are the lithosphere (land), hydrosphere (water), biosphere (living things), and atmosphere (air).

2) Importance of land stems from the fact that: Land holds the treasure of other important resources like oil, minerals, drinking water, trees giving oxygen & wood, eatables, and is the final recycling factory to produce reusable resources from the environment.

3) Soil is one of the three major natural resources, alongside air and water. Soil is made up of three main components – minerals that come from rocks below or nearby, organic matter which is the remains of plants and animals that use the soil, and the living organisms that reside in the soil.

4) the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms.

5) Soil is the thin layer of material covering the earth's surface and is formed from the weathering of rocks. It is made up mainly of mineral particles, organic materials, air, water and living organisms—all of which interact slowly yet constantly.

6) Humans only occupy five percent of the Earth's surface because oceans, deserts, rainforests, and glaciers cover much of the planet. The term for areas where humans permanently settle is called ecumene. Population growth and technology dramatically increase the ecumene of humans, which affects the world's ecosystems.