B cause they all blend in with snow so they can survive
I would think that an unweathered rock would be jagged while a weathered rock would be smooth because of water/wind or what ever weathered it.
Soil, water and food are all nonliving reservoirs of infection
Convection currents are caused by the colliding of cold and warm air. At night, air above water is warm and air above land is cold. The opposite is true in daytime. When the warm air hits the cold air, which is more dense, it is pushed upward. Then it travels laterally until it cools. It comes back down and pushes up the former cold air, which is now warm. This repeats many times.
Action potential is a mechanism of transfer of ions across the plasma membrane down their elctrochemical gradient. Action potential is regenerated by the influx of ions such as sodium in case of voltage gated sodium channels. The voltage gated channels can be either open or closed depending on the action potential. Depolarization of membrane leads to the opening of these channels that allow the sodium ions to enter the cell down their electrochemical gradient. The threshold of action potential is reached when the entry of sodium ions out reach the exit of potassium ions from the cell. This leads to the generation of action potential.
