In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.

Question: What planet is the easiest to observe? Answer: mars
Mars planet is the easiest to observe.

Question: What kind of reaction adds water to an organic molecule and breaks the large molecule into smaller molecules? Answer: hydration reaction
Hydration reaction kind of reaction adds water to an organic molecule and breaks the large molecule into smaller molecules.

Question: What part of the atmosphere is the heat source? Answer: stratosphere

The stratosphere is the heat source.