I regret buying the cheap TV at the electronics sale because it barely lasted a week before the screen went black and the volume stopped working based on the clues and the passage the author uses the word cheap to mean what

He uses cheap to mean it wasn't worth the money

quite an interesting way to teach topic sentences, because the answer to this question is the best definition of a topic sentence that one can present, it is as if answering the questions taught you how to do it, this is some real teaching, it is terribly well-done.

the topic sentence in this paragraph is:

topic sentences writers stay on track and keep a paragraph from becoming an aimless collection of sentences about an idea.

which incidentally tells you what a topic sentence should be.

is it "means of nourishment"