I have a question about the verb in the sentence:
Which animal do you think _____ most?
I chose 2)weighing because I think it could be re-write as
“Which animal do you think that weighs most?” and then we can ignore the “that” in the following clause and change “weighs” to “weighing” as we do in the relative pronoun sentence.
Am I correct?
“Weighs” would be the correct form of the verb “to weigh” here.
In your sentence, “which animal” can be replaced with “what”.
So in essence, it’s:
[What] weighs the most?
Because “weighs” is the correct form for he/she/it/that/what etc.
So your sentence should be:
Which animal weighs the most?