State reason for the following: (i) In human heart the walls of the ventricles are thicker than the auricles. (ii) During the breathing cycle even after forceful exhalation the exchange of gases continues. (iii) In green plants during the day carbon dioxide is generated in respiration but is not released out.

(i) In human heart ventricles have to pump blood to distant body parts, hence the
pressure is much higher, as compared to auricles which pump blood to closer lungs. Hence, walls of ventricles are thicker.
(ii) During breathing, even after forceful exhalation, gaseous exchange continues. This is because small amount of air still remains in our lungs and hence diffusion continues.
(iii) In green plants during the day carbon dioxide is generated in respiration, but is not released out, as this carbon dioxide is used to make glucose during photosyntheesis