Plant cells have cell walls, but animal cells don’t. Why might that be?

plant cell need cell wall whereas animal cell do not because the plants need rigid structure so that they can grow up and out. Cells have cell membrane. The membranes can flex. Animal cells can have varios shapes, but plant cells only have the shapes of plant cell wall.

Explanation:

the element that provides strength to the exoskeletons of clams and oysters is phosphorus. this is so because calcium carbonate is the main component in the shells.

explanation:

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.