pattern of veins in a leaf; may be parallel (as in monocots), reticulate (as in dicots), or dichotomous (as in Gingko biloba)

region of the lung that lacks proper alveolar ventilation (V) and/or arterial perfusion (Q)

body cavity on the anterior or front portion of an animal that includes the thoracic cavities and the abdominopelvic cavities

cavity within brain that contains cerebrospinal fluid

(heart) large inferior chamber of the heart that pumps blood into arteries

blood vessel that connects a capillary bed to a vein

exposure to cold required by some seeds before they can germinate

series of separate bones joined together as a backbone

members of the phylum Chordata that possess a backbone

transmission of disease from parent to offspring

small, membrane-bound sac that functions in cellular storage and transport; its membrane is capable of fusing with the plasma membrane and the membranes of the endoplasmic reticulum and Golgi apparatus

sense of spatial orientation and balance

physical structure present in an organism but that has no apparent function and appears to be from a functional structure in a distant ancestor

survival mechanism of bacteria facing environmental stress conditions

allopatric speciation that occurs when something in the environment separates organisms of the same species into separate groups