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: What do craters and rifts become when the fill with water? Answer: lakes

SOLUTION: Craters and rifts become lakes when they fill with water.

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

SOLUTION: Besides the concentration of dissolve oxygen and nutrients in the water, the availability of sunlight limits aquatic organisms.

PROBLEM: Question: What secretion initiates chemical digestion while also protecting the oral cavity? Answer: saliva

SOLUTION:
Saliva secretion initiates chemical digestion while also protecting the oral cavity.