Yes, they usually stay in groups, though they can't control that since plankton can't swim.
No, Phytoplankton is the smallest form of plankton.
yes! of course they do, millions of them can be in one place
Plankton is real because if you check in a book a plankton is a real live sea creature
You can get it in ponds, lakes and the sea, using a very fine net.