In this task, you are given a sentence and a question, you would be asked to create the answer which is contained in the sentence provided.

Sentence: Bicarbonate ions protects tissues of the central nervous system from changes in ph. Question: What protects tissues of the central nervous system from changes in ph?
bicarbonate ions

Sentence: Besides the concentration of dissolve oxygen and nutrients in the water, the availability of sunlight limits aquatic organisms. Question: Besides the concentration of dissolve oxygen and nutrients in the water, what other factor limits aquatic organisms?
availability of sunlight

Sentence: Nitrate levels and turbidity factors can have the greatest effect on the health of a river system. Question: Which factors can have the greatest effect on the health of a river system?

nitrate levels and turbidity