Plants are autotrophic meaning that they can produce their own food and structure from simple molecules in its surroundings (Textbox 3.1). The simple molecules that plants use are: water, carbon dioxide and minerals. Using light energy and suitable temperatures the plant can turn these “simple molecules” into more complex building blocks (carbohydrates, fats, proteins, and phytonutrients) to build up its own organs, growth regulation systems (homeostasis) and immune system, but also to store energy that can be used as food reserves.