————— have rootlike structures, called holdfasts, which
anchor them to the rocks.

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:

the answer is golgi apparatus

the statement is true

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.