4. Dialysis tubing lets in some molecules but not others. Dialysis tubing is a / (ar) membrane.

The answer is semipermeable membrane

Selectively permeable membrane.

Explanation:

Dialysis may be defined as the process of the removal of excess water waste and water from the cell. Dialysis can be used as the renal replacement therapy.

The dialysis tubes allows the movement of some selected particle only. This means that it acts as the semi permeable membrane that allows the entry and exit of some molecules only. Water can easily move through the dialysis tubing.

Thus, the correct answer is selectively permeable membrane.