<span>Simple glucose through carbon fixation
Carbon dioxide enters the plants through its leaves. Present under the surface of leaves are small holes through which carbon dioxide diffuses into the plant to fulfil its requirements. The leaf also gives off oxygen from these same holes in the leaves. These small holes are called stomata which is the plural form. the singular form of this word, or a single hole on the underside of the leaf is called a stoma.</span> After it enters, the plant prepares the other needed requirements to perform photosynthesis such as water, sunlight and other nutrients.
<span>Two main characteristics that distinguish autotrophs from heterotrophs are:
A~ Autotrophs produce their own food by either chemosynthesis or photosynthesis. Heterotrophs do not produce their own food. Heterotrophs obtain their food by consuming autotrophs or heterotrophs.
B~ Autotrophs are at the primary level in a food chain and Heterotrophs are at the secondary level or tertiary level in a food chain.</span>
