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.

Fact: Viruses often infect something killed by antibiotics. 
Question: Viruses often infect something killed by what?
Antibiotics.

Fact: Plants are essential for cellular respiration for all aerobic organisms. 
Question: What is essential for cellular respiration for all aerobic organisms.?
Plants.

Fact: change from one species to another occurs over geologic time. 
Question: What from one species to another occurs over geologic time?

change.