Which two things are most directly responsible for the cause of the seasons on Earth? Explain your reasoning.

The tilt of the earths axis and the sun.

Explanation:

As the earth rotates its important to know its tilted at a certain angle where the ray of the sun hits parts more than others. So, therefore, making some places warmer than others.

option a is correct i.e.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.

tissue

explanation:

it is actually formed by geoup of cells which is tissue