"which statement is best supported by the diagram?
(1)oxygen molecules entered the cell over time by active transport.
(2)water molecules are too large to enter or leave the cell, so they remained where they were at the start of the investigation.
(3)protein molecules are kept inside of the cell because the cell needs them.
(4)the protein molecules are too large to diffuse out of the cell."

Option D

Explanation:

Small, non polar and uncharged particles moves across the membrane by the process of simple diffusion in order move in and out of the cell

These substances includes,carbon dioxide, oxygen, ethanol, water, urea et cetera.

The large polar and charged molecules such as carbohydrates, fats, protein and ions cannot freely diffuse through the membrane and are transported by the help of carrier protein as they are too large.

Hence, the correct answer is option D

option c is the correct answer.