자극

The act of returning something to its original state or simplifying a complex idea into its basic elements; in science, it also refers to chemical reduction.

Describing a process or change that cannot be reversed or returned to its original state. Often used in environmental science and medicine.

To be changeable, variable, or unstable. Not fixed in nature or state.

A sign or indication that something is happening or about to happen, especially something bad like an illness or economic crisis.

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.