Question

read the excerpt.
select the correct answer and press the submit button
read this part of the text. which sentence is the best summary of this part?
a scientists are usually wrong about the medicines that they think will work.
b the cause of most diseases in humans is still unknown to researchers.
c new medicines have to destroy the germs that cause illnesses without harming anyone.
d it can cost more than two billion dollars to invent a new medicine that gets approved.
of the molecules that show promise, scientists pinpoint the ones that could successfully enter our bodies, seek and destroy the bacteria, and leave without harming us. sometimes they tweak the molecules shapes to make them safer and better. finally, they choose a handful of molecules - one of which may become the \champion molecule\ - to double - check that they wont actually poison anyone!

Explanation:

The text excerpt focuses on the process of developing new medicines. It mentions that scientists select molecules that can enter the body, destroy bacteria, and leave without harming us. This is in line with option C which emphasizes that new medicines must destroy disease - causing germs without harming anyone.
Option A is incorrect as there is no mention in the text about scientists being wrong about medicines. Option B is not relevant as the text is not about the cause of diseases being unknown. Option D about the cost of inventing a new medicine is not discussed in the given excerpt.

Answer:

C. New medicines have to destroy the germs that cause illnesses without harming anyone.