Theme 4: Structure and function are correlated at all levels of biological organization.• Form fits function; how a device works is correlated with its structure.○ Applied to biology, this theme is a guide to the anatomy of life at all its structural levels.○ For example, the thin, flat shape of a leaf maximizes the amount of sunlight that can be capturedby its chloroplasts. ○ The phenomenon of life defies a simple, one-sentence definition.○ We recognize life by what living things do.