Select the most appropriate option to fill in blank no. 2.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1, i.e., reason.
The sentence is explaining why whales and dolphins are warm-blooded, so the correct word should express a cause or explanation.
Reason – correctly fits; it means the explanation or cause.
Motive – usually refers to an intention behind an action (not suitable here).
Ground – though it can mean basis, it's more formal/legal and less natural here.
Thought – doesn't fit the context of explanation.
Final Sentence: The reason for them being warm-blooded is because they belonged to the mammal group.
Conclusion: The most appropriate word to fill blank 2 is reason.