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.

[Q]: Question: A _____ in the population cold lead to less food availability. 
 Answer: increase
[A]: As the population increases, the food supply, or the supply of another necessary resource, may decrease.


[Q]: Question: Rick had a rock (Rock A) from 1000 feet beneath the crust's surface. He later dug 3000 feet deeper and got a second rock (Rock B). Which rock is likely older? 
 Answer: Rock B
[A]: Older rocks are at the bottom and younger rocks are at the top.


[Q]: Question: Yolanda's kidneys were not working as well and removed less water from her blood. Her blood now looks 
 Answer: darker
[A]:
If the kidneys remove less water from the blood, the blood will look darker, because there is less water in it.