Question

which answer gives only facts?
it would be great if everyone memorized their fingerprints.
everyone has a unique set of fingerprints.
fingerprints look weird close up.

Explanation:

A fact is a statement that can be proven true. "It would be great if everyone memorized their fingerprints" is an opinion. "Fingerprints look weird close up" is also an opinion as "weird" is a subjective description. "Everyone has a unique set of fingerprints" is a scientific fact that can be verified.

Answer:

Everyone has a unique set of fingerprints.