For some conditions, having one mutated copy of a gene in each cell is advantageous,
while having two mutated copies causes disease. The best-studied example of this
phenomenon is sickle cell disease: Having two mutated copies of the HBB gene in each
cell results in the disease, but having only one copy provides some resistance to
malaria. This disease resistance helps explain why the mutations that cause sickle cell
disease are still found in many populations, especially in areas where malaria is
prevalent.
What mechanism of evolution is this?
Founders effect
Mutations
Geographic Isolation
coevolution

because the asteroid belt is between the mars and jupiter orbits, it is around 2.2 to 3.2 astronomical units (au) from the sun – which is approximately 329,115,316 to 478,713,186 km. the average distance between objects is a massive 600,000 miles.

explanation:

[content deleted] - user123802726recklesschicken

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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it is either c or d and i know for sure it is not a or b