Discuss how certain elements perform Constraction of muscle and conduction of nerve impulse, Transport, Storage and Utilization of Oxygen, formation of hormone in our body.

Discuss how certain elements perform maintenance of formation of teeth and bone, functioning of enzymes, coagulation of Blood in our body.

Discuss how certain elements perform maintenance of water balance, functioning of the heart, acid-base equillibrium in our body.

Go through the following statements (i) Vagus nerve decreases the rate of impulse formation from the SA node and its conduction (ii) As the human heart is myogenic in nature, the rate of formation and conduction of cariac impulse cannot be changed by the action of nerves (iii) The end of T-wave in ECG marks the end of systole. (iv) If the P-wave in ECG is inverted , it indicates that SA node fails to initiate impulse and the atrial muscle depolarises by the impulse originating in A.V. node. Which of these are correct ?