Parallel structure means using the same grammatical form for related ideas. In this sentence, all the activities are in the gerund form.
"Lay" is the past tense of "lie," which is appropriate for indicating the cat's action in the past.
The main idea encompasses the overall information presented in the passage about elephants being the largest land animals and their unique features.
"They're" is the contraction for "they are," which correctly fits the context of the sentence.
A thesis statement clearly states the main argument or claim that will be supported throughout the essay.
