Question

14. What direction do freshwater fish pump salt across their gills?

Answer 1

@Phebe Well, freshwater fish are in a hypotonic solution so they gain water. I am not sure about salt, it was my understanding that the fish do not move salt in the gills. Instead they move water. But, freshwater fish cell's have a higher concentration of salt in their cells than the conc. of salt in the water. They need to maintain the salt gradient though.

Answer 2

@mrdoldum can u specify alil more plzz

Answer 3

Well, freshwater has a lower concentration of salt in it than the concentration of salt in the fish cells. This means that water will rush into the cells of the freshwater fish due to osmosis. This is a chemical/physics event to equalize the salt concentrations. Freshwater fish need to have a higher salt gradient so I would guess that they pump salt into the cells. @Phebe