Calcium concentrations in water are lower than in blood.How would calcium ions be taken up by the gills?

Question

Quizplus · Accepted Answer

Active transport is the process in which the cell uses energy to move ions or molecules against their concentration gradient. Since calcium concentrations in water are lower than in blood, the gills need to actively transport calcium ions into the body to maintain proper levels. Osmosis, diffusion, and facilitated diffusion are passive processes that do not require energy and would not be sufficient for taking up calcium ions. Exocytosis is the process of releasing substances out of a cell and has no relation to calcium uptake.

Calcium Concentrations in Water Are Lower Than in Blood