The Periodic Table of the Elements categorizes elements primarily by the number of protons in their nucleus (atomic number) and secondarily by the characteristics they exhibit.

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

Heredity is the passing on of physical or mental characteristics genetically from one generation to another. Heredity is made possible via large strings of chromosomes which carry information encoded in genes.

The Kuiper Belt is similar to the asteroid belt but much larger. Extending beyond the orbit of Neptune, it contains objects composed mostly of frozen methane, ammonia, and water. Most notably, the Kuiper Belt is home to Pluto, a dwarf planet that, until a 2006 reclassification, was considered the ninth planet of the solar system.

Small quantities of certain minerals like iron, calcium, magnesium, and salt are important for nutrition and health.