The first sentence. When you're talking about more than one elf it is elves not elfs.
Answer:
If I win 1 lakh rupees in a speech contest then probably I will do something that I won't regret later on.
I think the answer is individual paragraphs because you break it up so after the whole essay you move to paragraphs than sentences then words then punctuation so that its easier to find errors.
The speech was enthusiastic and got the team excited that they could win the game. Someone at a theme park would be most ebullient because they would be most enthusiastic from having fun.
B. Teenagers have a lot of variation in their behavior
