A numerical measure of the strength and direction of the relationship between two variables, ranging from -1 to 1.

The outer layer of an organ or structure, such as the cerebral cortex of the brain or the cortex of a plant root.

A group of steroid hormones produced by the adrenal cortex, including glucocorticoids and mineralocorticoids, which regulate metabolism, immune response, and salt balance.

A type of vector used in molecular biology that combines features of plasmids and phages, allowing for the cloning of large DNA fragments.

An organic substance found in the outer layers of the scales of early vertebrates, believed to be a precursor to bone.

The first leaf or leaves that appear during the early development of a seedling, often involved in nutrient storage or photosynthesis.

An extinct group of early reptiles, believed to be ancestors of modern reptiles and mammals.

A form of camouflage where the upper parts of an animal are darker than the lower parts, helping to reduce visibility from above and below.

A system in which two substances are transported across a membrane simultaneously, often with one substance moving down its concentration gradient to drive the transport of the other.

A chemical reaction in which an exergonic reaction drives an endergonic reaction, such as the use of ATP hydrolysis to power other cellular processes.