Why would a scientific theory be revised over time ? ?

A scientific theory may be revised overtime because it goes to the loop of science which what's the scientific theory to test several times each time a different product may be shown or every now and then a different product may be shown so therefore over time as it goes through the loop of science a scientific theory may change or be revised

Ribonuclease activity is a type of nuclease that catalyzes the degradation of rna into small components.