Where do the electrons that enter the electron transport chain come from?

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

Which event would lead to primary succession of a forest?

Been sitting here trying to take this test and don't know this answer! place the events of a feedback mechanism associated with body temperature in the correct order. ·nerve cells send message from skin to the brain ·body returned to normal temperature around 98.6 degrees f ·temperatures regulation center in the brain sends out signals ·body temperature exceeds 98.6 degrees f ·sweat glands throughout the body activate to cool off skin surface it is a 1 through 5 question in biology!