Which of the following words best describes synthesis?

change

reading

emotion

science

change describes synthesis better because it's a chemical change/reaction. aka combination of chemicals to make a different chemical/reaction.

change

Explanation:

When you synthesize, you make something new out of different elements. And when something becomes different, it inevitably changes.

So synthesis, which means, among other things, the formation of complex compounds from simpler ones, involves a change. Thus, change would be the best word to describe the term synthesis.