Infrosomes are composed of .........?

In the given figure,what do $a$ and $b$ represent respectively?

Which type of microscope is useful for studying the shape of a cell in motion?

The main difference between pinocytosis and phagocytosis is:

Select the correct option for the following statements:
$(i)$ $A$ chromosome in which the centromere is situated near the middle is called a metacentric / submetacentric chromosome.
$(ii)$ The air vacuole / contractile vacuole helps in osmoregulation.

Where does protein synthesis occur in animal cells?