Assertion(A): Diffusion takes place only along a gradient and does not use energy.
Reason(R): Proteins in the membrane are responsible only for active transport.
Choices for Assertions and reasons:
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.