Answer: D) By decreasing the activation energy of a reaction
A catalyst is a substance that speed up the rate of chemical reaction without affecting the product of the reaction. They only affect the rate of reaction not the yield of reaction.
Catalyst provide an alternative reaction pathway that has lower activation energy than that of uncatalysed reaction. It increases the frequency of collision and because of these greater collision which lowers the activation energy of the reaction.
The pulmonary circuit transports blood to the lungs. The blood is oxygenated there and then carried back to the heart. Gaseous exchange happens in the lungs:
Carbon dioxide diffuses from the blood into the air in the alveoli.
Nutrients move directly into the esophagus where it continues to be warmed and lubricated as it moves toward the stomach.
A structure formed from molecules that combine to make up cells is called an atom.
The second stage is where the brain waves become larger and punctuated with occasional sudden bursts of electrical activity. In this stage the eyes are not able to respond to light. Non-rem sleep has 3 stages. The first stage is the twilight zone which is between full wakefulness and sleep and the third stage constitutes the most profound state of unconsciousness.
