plural of belief system

(physiology) The parts of an animal body comprising the heart, blood vessels (arteries, veins, and capillaries), and blood, which circulate the blood around the body.

(medicine) A blood group system, the second most important after the ABO system, and important in human blood transfusion, whereby blood types are classified according to the presence ("positive") or absence ("negative") of potentially over 50 antigens, of which the most commonly referenced is RhD.

In Latin, the three perfect tenses: perfect, future perfect, and pluperfect or past perfect, as contrasted with the present system: present, future, and imperfect. A verb in the perfect system indicates an action that has completed.

In Latin, the three simple tenses: present, future, and imperfect, as contrasted with the perfect system, the three perfect tenses: perfect, future perfect, and pluperfect. Verbs in the present system tend to indicate an action that has not completed.

plural of nervous system

plural of immune system

A hierarchy of values that all moral beings have, reflected in their choices. Most people's value systems differ. It's an individualistic concept. One's value system is molded by one's virtues or vices, and experiences.

A pushchair with detachable carrycot or car seat.

plural of travel system