In which process does the cell use a gracile to move molecules into the cell

Cell membranes

Explanation:

Cell membranes act as barriers to most, but not all, molecules. Development of a cell membrane that could allow some materials to pass while constraining the movement of other molecules was a major step in the evolution of the cell. Cell membranes are differentially (or semi-) permeable barriers separating the inner cellular environment from the outer cellular (or external) environment.

the dark variety, as they are not visible on the dark tree barks

explanation:

where is the scientific experiment?