The lowest deepest layer consists of fragments of the parent bedrock. Types of soil are classified according to their organic content, mineral composition, pH, and size of rock particles. Different types of plants grow best in different types of soil. The biosphere , the part of the earth where we live is about 20 km thick. It extends from the ocean floor to the highest point in the atmosphere where life is found.
Autotrophs are organisms that can use inorganic compounds to make organic nutrients.
Most carry on photosynthesis and a few carry on chemosyntheses. Heterotrophs are divided into groups depending on what they eat and how they obtain food. Herbivores eat plants. Carnivores eat other animals. Predators kill and eat their prey.