Explanation:
Explanation:

In operculate fish (fish that have a bony cover over their gills called the operculum), the breathing process involves water moving through the mouth, over the gills, and out through the operculum.

Here's the process in detail:
- Step 1: The fish opens its mouth and takes in water.
- Step 2: The water passes over the gills, where oxygen is absorbed and carbon dioxide is expelled.
- Step 3: The water exits through the operculum (a bony flap covering the gills), which helps to expel the water from the gill chamber.

Let’s review the other options:

#A. mouth and passes it out through the same way
- This is incorrect. Water does not exit through the same way it enters. The water enters through the mouth but exits through the operculum.

#C. operculum and passes it out through the mouth
- This is incorrect. The operculum is not used to take in water; it is involved in expelling the water after it has passed over the gills.

#D. operculum and passes it out through the nostrils
- This is incorrect. Water does not enter through the operculum, nor is it expelled through the nostrils in operculate fish.

#E. nostrils and passes it out through the operculum
- This is incorrect. While some fish may use their nostrils for sensing chemicals or for limited water intake in certain species, the primary route for water intake is through the mouth, not the nostrils.


Summary:
In operculate fish, water enters through the mouth and exits through the operculum after passing over the gills.