For question 2, here's what I wrote. Is this the same as the answer?

Consumers are no more likely to buy products whose safety was tested on cultures of human cells than they are to buy products whose safety was tested on animals.

Two things being compared: products whose safety was tested on cultures of human cells vs. products whose safety was tested on animals

Quality/Characteristic being compared: which products are consumers NOT more likely to buy?

Winner: products whose safety was tested on human-cells cultures