Answer:
A scientific theory is a well-substantiated idea or hypothesis which is supported by the facts obtained from the repeated experiments and the observation related to the natural phenomenon.
The theories are not permanent rather they change or modified with time, they could be even rejected. The reason for the rejection of old theories or replacement of the old theory with new theories is done as more information is gathered and the new theory which could explain the natural phenomenon more accurately will be accepted.
Since the theory gets modifies and rejected at any given time, therefore, they are always considered current theory which could be changed later when new data is gathered.