Afreshwater fish regulate its salt levels by pumping salt outward across its gills true or false?
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False

Explanation:

The salt concentration inside the body of freshwater fish is higher as compared to the water in which it live . However this is not the the case with marine fish which have low salt concentration in their blood  as compares to the salt in the sea water. In order to maintain sufficient salt in the fresh water fish body, specialized cell in the gills take ions from water and transport it into the blood.  Thus it can be said that A freshwater fish regulate its salt levels by pumping salt inward across its gills

b a mature ovary of a plant.

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.