Autotrophs are groups of organisms that are capable of manufacturing their own food (organic molecules) through the fixation of carbon dioxide. There are two types of autotrophs:
<em>Photoautotrophs fix carbon dioxide by using light as the energy for driving the process.</em>
<em> </em><em>Chemoautotrophs f</em><em>ix carbon dioxide by using energy from the oxidation of inorganic molecules such as magnesium, or sulfur.</em>
Chemoautotrophs usually inhabit extreme environment such hot vents, deep sea, etc.
