Erosion and deposition constantly change Earth’s surface. Erosion carries natural materials like rock and soil from one place to another. Through deposition, these natural materials may be deposited in areas where they build up over time.

Which landform results from the deposition of materials in a valley during volcanic eruptions?

sill
mud pot
caldera
lava plateau

The correct answer is "lava plateau".

Explanation:

Lava plateau is a landform that is formed from the deposition of materials after many successive volcanic eruptions. These landforms are formed particularly after many quiet explosions, which produce very fluid lava. Pyroclastic plateaus is very similar to lava plateau, with the difference that they are comprised of pyroclastic rocks, which have agglomerates, tephra, and volcanic ashes.

D. Lava Plateau

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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the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.