neurons are cells of the nervous system. as part of its normal function a neuron pumps sodium ions out of the cell and potassium ions into the cell which statement decribes the role of energy in this proes

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.

a symbiotic relationship with the mitochondria

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.