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The scientific study of the human mind and its functions, especially those affecting behavior in a given context.

Physical substance in general, as distinct from mind and spirit; in physics, that which occupies space and possesses rest mass.

An animal that naturally preys on others. A predator in the food chain.

The process of material (such as sand or mud) settling or being deposited, especially by water, ice, or wind. Sedimentation.

The outside part or uppermost layer of something. It can be a physical surface or a figurative outward appearance.

The force that attracts a body toward the center of the earth, or toward any other physical body having mass.

A long period of reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets.

The remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.

Matter that settles to the bottom of a liquid; sediment. Often used in geology to describe layers of sand, mud, or stone.

The point or place where something begins, arises, or is derived. It refers to the historical or biological roots of an object, idea, or species.