In this task, you are given a question and answer for that. The answer will fill in the blank or will complete the unfinished question. Your task is to provide an explanation based on the given question or fill-in-the-blank statement, and answer.

Question: What would happen to the atmosphere as Jim climbed higher up a mountain? 
 Answer: it would become less dense
The density of the atmosphere decreases with an increase in the height above sea level (altitude).

Question: Two species with very similar DNA are probably _____ related. 
 Answer: closely
The more similar the DNA molecules of different species are, the closer the relationship is likely to be.

Question: If air cools, it becomes _____ dense. 
 Answer: more

Warm air is less dense than cool air, so it rises higher in the troposphere.