The variability in marine salinity between habitats dose not impact the fish living there

Since water is generally shallow, photosynthetic processes are possible for marine life which attracts more organisms to their primary food sources. Since the land is near shallow waters, discharges of nutrients from the soil are brought into the sea for the consumption of organisms. Aside from these reasons, periodic upwellings in the sea also provide cool and nutrient rich waters for different species.

the glands which are associated with each description is given below:

pancreas - is an endocrine and exocrine gland that secretes juices with enzymes for digestion. salivary glands- with protection and digestion in the mouth. liver- secretes bile for digestion.   lachrymal glands - secrete tears to moisten eyes and protect them from particles and infection.   sweat gland -regulates water, salt, and temperature. oil glands - to form a protective barrier on the skin.   goblet cells - secrete mucus for protection.