what cell structure is largely responsible for controlling the entry and exit of substances into or out of the cell?

Analogy- 1 is to arete as 5 is to cirque horn glacial valley hanging valley

The observations of hooke and van leeuwenhoek documenting the existence of microscopic cells formed the basis of what important theory? a. the cell theory stating that all living things are composed of cellsb. the theory of spontaneous generation, which held that life forms could arise spontaneouslyc. the theory of chemotherapy, or use of antimicrobials to destroy pathogenic organismsd. the germ theory of disease and causative agents

Which phase of the cell cycle ensures that identical copies of the dna are made for daughter cells?