TASK DEFINITION: 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.
PROBLEM: Fact: Most animals without backbones have a nervous system. 
Question: Which type of system do most animals without backbones have?

SOLUTION: Nervous system.

PROBLEM: Fact: passive immunity lasts only as long as the antibodies survive in blood. 
Question: passive immunity lasts only as long as the antibodies survive where?

SOLUTION: blood.

PROBLEM: Fact: Black holes form from stars with relatively short lives. 
Question: Which type of star is most likely to end up as black hole?

SOLUTION:
relatively short lived.