11. The is the hard outer layer of the Earth about 100 km (62.14 mi) thick.
A crust
B troposphere
C atmosphere
D lithosphere

A) crust

Explanation:

 lithosphere

Explanation:

The upper mantle and crust together form a rigid layer of rock called the Lithosphere, which is 0-100 km thick. The Lithosphere has broken into plates that float on the Asthenosphere. The Asthenosphere is 100-700 km deep.

brainliest plz

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.  

read more on -

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus