1 adj Social means relating to society or to the way society is organized. ADJ n. ...the worst effects of unemployment, low pay and other social problems., ...long-term social change., ...changing social attitudes., ...the tightly woven social fabric of small towns., ...research into housing and social policy.
The human circulatory system (simplified). Red indicates oxygenated blood carried in arteries, blue indicates deoxygenated blood carried in veins. Capillaries, which join the arteries and veins, and the lymphatic vessels are not shown.
In general the circulatory system of blood vessels may be broken down into those vessels that deliver oxygenated blood to tissues: the arteries, arterioles, and capillaries, and those vessels that return blood with carbon dioxide for gas exchange: the veins and venules.n general the circulatory system of blood vessels may be broken down into those vessels that deliver oxygenated blood to tissues: the arteries, arterioles, and capillaries, and those vessels that return blood with carbon dioxide for gas exchange: the veins and venules.