For those individuals who have an allergic reaction to cats, a company in Los Angeles promises relief. They offer a new line of cats genetically modified to eliminate or reduce their allergy-causing properties. The development of this new line of cats most
likely involved
(1) using natural selection to produce a new variety of cat (3) changing the behavior of cats
(2) altering the reproductive rate of cats
(4) manipulating the DNA of cats

1 or 4..

Explanation:

Answer is D. Altering the DNA of cats

Explanation:

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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