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: The concentration of the hydrogen ion in a solution can be calculated when what is known? Answer: ph

SOLUTION: The concentration of the hydrogen ion in a solution can be calculated when the ph is known.

PROBLEM: Question: What is the ratio of solutes in a solution to a volume of solvent in a solution known as? Answer: osmolality

SOLUTION: Osmolality is the ratio of solutes in a solution to a volume of solvent in a solution.

PROBLEM: Question: Plants not only contribute food but what else for organisms? Answer: oxygen

SOLUTION:
Plants not only contribute food but oxygen for organisms.