The Earth's rocks fall into three categories based on how they're formed. Igneous rock (granite, basalt, obsidian) is formed from the hardening of molten rock (lava), sedimentary rock (shale, sandstone, coal) is formed by the gradual despositing and cementing of rock and other debris, and metamorphic rock (marble, slate, quartzite) which is formed when existing rock is altered though pressure, temperature, or chemical processes.

The cerebrum is the major part of the brain and is responsible for the main senses (thinking, hearing, seeing).

Cell division is the process by which cells replicate genetic material in the nucleus and consists of several phases, beginning with interphase and ending with cytokinesis.

Mass is the amount of matter something has while weight is the force exerted on an object's mass by gravity.  So, although a person's mass doesn't change when going from the Earth to the Moon, their weight will decrease because the force of the Moon's gravity is much less than that of Earth.

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.