Assertion (A): Cells need nutrients, O2, essential substances, and also the removal of harmful substances for healthy functioning.
Reason (R): It is essential to have efficient mechanisms for the movement of these substances to the cells and from the cells.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.