TASK DEFINITION: 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.
PROBLEM: Question: Calcium ion is an example of what kind of messenger? Answer: second

SOLUTION: Calcium ion is an example of a second messenger.

PROBLEM: Question: The concentration of hydrogen ions in a solution is called? Answer: acidity

SOLUTION: The concentration of hydrogen ions in a solution is called acidity.

PROBLEM: Question: What is the process that allows organisms with better traits to survive and produce? Answer: natural selection

SOLUTION:
Natural selection is the process that allows organisms with better traits to survive and produce.