Assertion (A): Frogs help maintain ecological balance.
Reason (R): The species which maintain ecological balance serve as an important link in the food chain and food web.
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.