An ecological pyramid is a graphical representation used to illustrate the relative distribution and transfer of energy, biomass, or numbers of organisms at various trophic levels within an ecosystem.

States of matter means the distinct physical forms in which matter can exist, characterized by differences in the arrangement of particles.

The reactivity series of metals is a fundamental concept in chemistry that provides insights into how metals interact with other substances.

Vaccination, a medical process, person is intentionally given a vaccine, contains weakened, killed, or modified form of a microorganism.

Acid rain is a form of environmental pollution in which rainfall or other forms of precipitation become acidic.