The best answer is A
Saltwater fish are hypotonic to their surroundings. This means their blood has a higher water concentration than the surrounding sea water.
Due to the fact that there is more salt and less water outside their bodies, there is a tendency to take in salt and lose water.
To counter this, salt water fish drink a lot of the sea water and urinate very little. Special cells in the gills actively eliminate salt at the cost of extra energy and these fishes do not absorb any salt from the water they drink.
They are reactants because they are present before the reaction
An action potential will not occur unless the membrane potential AT THE VOLTAGE GATED SODIUM CHANNEL reaches a level called THRESHOLD.
An action potential refers to the change in the electrical potential which occurs as a result of the passage of impulses along the membrane of muscle cells or nerve cells. An action potential occurs when there is depolarization of the cell membrane to the threshold stage.
Answer: Effector cytotoxic T cells
Explanation:
Cells infected with a virus or another internal cellular infection are immediately killed by effector cytotoxic T cells.
