Obligate Relationships

Q. With regard to the assertion and reason, choose the correct option.
Assertion [A]: Extinctions have a domino effect.
Reason [R]: The extinction of one species affects the survival of other species that are in obligate relationship with the extinct one.

1. Both A and R are correct and R explains A
2. Both A and R are correct but R does not explain A
3. A is correct but R is incorrect
4. Both A and R are incorrect