How does this excerpt help develop the main idea in "This Mix Turns Pink When Sunscreen Wears Thin"?

Hello. You did not show the passage to which this question refers, which makes it impossible for this question to be answered accurately. However, I will try to help you in the best possible way.

It is only possible to know, in fact, how the passage develops the central idea of the text, after reading it. However, we can affirm that to develop this idea, the excerpt must address the main idea within a situation, reinforcing the importance and applicability of this subject in practice and making the reader recognize it and be able to reflect on it.