Question

why do adult fingerprints last longer on a surface than a childs fingerprints?
a adults have more natural oils on the fingers
b children have cleaner hands than adults
c adults have deeper ridges
d adult fingerprints are larger

Explanation:

Fingerprints are formed by the ridges on the skin. Adults have more natural oils on their fingers. These oils help the fingerprint residue (from the ridges) to adhere better to a surface and last longer. Children's hands may have relatively less of these natural oils. Option B is incorrect as it's not about hand cleanliness in the context of fingerprint longevity. Option C, deeper ridges might not be the main factor compared to the oil presence. Option D, larger size is not the key reason for longer - lasting.

Answer:

A. Adults have more natural oils on the fingers