The filtration units of kidneys are called:

Why does absorption of digested food occur mainly in the small intestine?

$(a)$ Name the hormone which is released into the blood when its sugar level rises. Name the organ which produces this hormone and its effect on blood sugar level. Also,mention the digestive enzymes secreted by this organ with one function of each.
$(b)$ Explain the need for chemical communication in multicellular organisms.

How do the guard cells regulate the opening and closing of stomatal pores?

What will happen if mucus is not secreted by the gastric glands?

If salivary amylase is lacking in the saliva,which of the following events in the mouth cavity will be affected?