Write a correct answer to the given question based on its associated fact. Make sure that your answer is contained in the associated fact. Don't be creative and introduce any new word that is not mentioned in the associated fact! Remember that the associated fact has been rearranged to form the question. So, the correct answer words must lie within the associated fact. The correct answer can be a word, phrase, or even a sentence.

[Q]: Fact: the average number of individuals per unit of area affect the balance of the environment. 
Question: The average number of individuals per unit of area affect the balance of .?
[A]: the environment.


[Q]: Fact: Ink is used for hiding from predators by some animals that eat small crabs. 
Question: Some animals that eat small crabs also use this for hiding from predators:?
[A]: ink.


[Q]: Fact: The tiny grains of pollen from plants are the ova and spermatozoa. 
Question: What are the ova and spermatozoa of plants?
[A]:
Pollen grains.