Brine shrimp live in salt water, but the level of salt in the water where they reside can differ dramatically from day to day or
longer time scales. In very high salt concentrations, a brine shrimp _____ salt across its gills and maintains an internal salt concentration that is _____ relative to the water where it lives. In lower salt concentrations, a brine shrimp _____ salt water across its gills and maintains an internal salt concentration that is _____ relative to the water where it lives.
The correct answer is "excretes; hypotonic; absorbs, hypertonic".
Explanation:
Cell's homeostasis is only conserved in an isotonic solution, since cells that are in an hypertonic solution (high salt concentration) tend to loss water, and in hypotonic solution (low salt concentration) tend to absorb water. Brine shrimp lives in waters that are both, hypertonic and hypotonic and has adapted to overcome this issue by excreting and absorbing salt across its gills. In very high salt concentrations, a brine shrimp "excretes" salt across its gills and maintains an internal salt concentration that is "hypotonic" relative to the water where it lives. In lower salt concentrations, a brine shrimp "absorbs" salt water across its gills and maintains an internal salt concentration that is "hypertonic" relative to the water where it lives.
