Which statements describe the solar system ? Check all that apply.

The solar system includes the Sun, planets, and moons.

The planets travel in orbit around the Sun.

Other planets help scientists understand Earth history.

Explanation:

I think this is what you want

The solar system is the sun and everything that orbits around it. It includes the planets and their moons as well as numerous asteroids and comets. These objects are all held in orbit around the sun by the sun's strong gravity.

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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