Some plant cells produce their own energy through photosynthesis which is the process by which sunlight, carbon dioxide, and water react to make sugar and oxygen. Animal cells cannot produce their own energy and, instead, generate energy when mitochondria consume outside sugar and oxygen through aerobic respiration.

During a chemical reaction molecules and atoms (reactants) are rearranged into new combinations that result in new kinds of atoms or molecules (products).

An ecosystem is a biological community of interacting organisms and their physical environment. This includes both the biotic (living) and abiotic (non-living).

The rows of the Periodic Table are called periods and contain elements that have the same number of electron shells ordered from lower to higher atomic number.

The speed of light varies based on the material that the waves are passing through. The refractive index of a material indicates how easily light travels through it compared to how easily light travels through a vacuum. For example, the refractive index of water is 1.33, meaning that light travels 1.33 times faster in a vacuum than it does in water.