a. SAN generates as action potential which stimulates atrial systole. b. ECG is an electrical representation of the graphical activity of the heart during a cardiac cycle. c. The cardiac output of a normal man will be much lesser than an athlete. d. The wall of right ventricle is much thicker than the left ventricle e. In pisces the two separate circulatory pathways are present, hence they have double circulation. f. The clsoed circulatory pattern is considered to be more advantageous than open circulatory pattern. g. Glucose is absorbed by simple diffusion through lymph in lacteales present in the intestinal villi. h. The SAN can generate the maximum number of action potential i.e. 140-150 `mi n^(-1)` in neonates, and is responsible for initiation and maintenance of the rhythmic contractile activity of the heart. i. Angina can occur in any age but more common among the neonates and infants. j. heart failure is sometimes called congestive heart failure because congestion of the blood vessels is one of the main symptoms of this disease.