You are given a question, its answer, and a sentence that supports the question, i.e., the answer to the question is inferable from the sentence. In this task, you need to paraphrase the given sentence so that the paraphrased sentence still supports the question i.e. you can still infer the answer to the question from the paraphrased sentence. Do not write a paraphrase with a minor change in the given sentence e.g. replacing the word "one" with "a". Instead, try to write a paraphrase that contains new words, i.e. the words that are not present in the input sentence.
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Question: Question: The concentration of the hydrogen ion in a solution can be calculated when what is known? 
Answer: ph. 
Sentence: The concentration of the hydrogen ion in a solution can be calculated when the ph is known.

Answer: If the ph is known then the concentration of the hyrdorgen ion in a solution can be calculated.


Question: Question: Which human organ system produces hormones to regulate growth, development, and reproduction? 
Answer: endocrine. 
Sentence: The endocrine system produces hormones to regulate growth, development, and reproduction.

Answer: By producing hormones, the endocrine system regulates growth, development, and reproduction.


Question: Question: What crucial role does beneficial fungi play? 
Answer: balance of ecosystems. 
Sentence: Beneficial fungi play a crucial role in balance of ecosystems.

Answer:
A crucial part of the balancing of ecosystems is done by beneficial fungi.


