Essential fatty acids (EFAs)Fatty acids that cannot be constructed within an organism from other components (generally all references are to humans) by any known chemical pathways; and therefore must be obtained from the diet.

In which of the following ways is the function of the surface of a microsphere similar to the function of an actual cell membrane? a.both make it possible for the conditions in the interior to be different from the conditions outside. b.both provide a barrier that keeps water from flowing across it so the interior remains dry. c.both separate the rna that forms in the interior from any rna that might form in the environment. d.both can actively move molecules into the interior or out into the surrounding environment.

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time

Acommon kind of mechanical weathering is called