A set of criteria to establish a causative relationship between a microbe and a disease.

Relating to or affecting the colon or large intestine.

The scientific study of atmospheric dust and airborne particles.

An instrument used to measure the amount and size of airborne dust particles.

A leaf structure characteristic of C4 plants where bundle sheath cells surround vascular bundles.

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate.

A chemical element (symbol Kr), a noble gas used in lighting and photography.

The absolute temperature scale starting at absolute zero, used in scientific measurements.

A fibrous protein forming the main structural constituent of hair, nails, feathers, and the outer layer of skin.

Inflammation of the cornea and conjunctiva of the eye.