Animals are protected in a zoo also. Is there any difference between a zoo and wildlife sanctuary?

Yes there are differences between the protection given to animals in zoo and wildlife sanctuaries. These differences are listed below:

In zoo animals are not protected in their natural environment or habitat whereas in wildlife sanctuaries they are protected in their natural environment.

Wildlife sanctuaries mostly aim for the protection of some particular species whereas in zoos animals are bought and they rear them but not look for protection of particular species.

Zoos are mostly trade sought of which mostly aims for money whereas the primary goal of wildlife sanctuaries is the protection of animals and not to use them for trade related aspects.

There are strict rules and regulations in wildlife sanctuary regarding entry of every person but the case is not same with the zoos.