The sodium-potassium ion exchange pump a) must reestablish ion concentrations after each action potential. b) transports sodium ions into the cell during depolarization. c) transports potassium ions out of the cell during repolarization. d) moves sodium and potassium opposite to the direction of their electrochemical gradients. e) depends on a hydrogen gradient for energy.

Moves sodium and potassium opposite to the direction of their electrochemical gradients. (Ans. D)

Explanation:

Sodium potassium pump: It is present in many plasma membrane of the cells. A protein which is present on the many cells is maintained the internal and external environment concentration by maintain internal concentration of potassium higher than outside and internal concentration of sodium lower than outside.

With the help of the ATP, moves sodium and potassium opposite to the direction of their electrochemical gradients. Two potassium ions are imported and three sodium ions are ejected in a cell, In a single pump cycle.

thermophiles, notice the prefix thermo.

answer: grassland biomes are closer to the equator and receive more rain.

grasslands are biomes that are dominated by grasses rather shrubs and trees. savanna are biomes that exhibit grasses, shrubs and small tree as vegetation. grasslands are located near the equator of the earth. these are found in north america. savanna biomes are found in africa, south america, australia and india. grassland exhibit moderate climatic conditions, it receives   amount of rainfall higher than savanna.   therefore, savanna exhibit dry and hot climatic conditions.