How and why does the latitude of a place on earth affect its average temperature?

Explanation:

Higher latitudes receive less light intensity from the sun than lower latitudes. This is due to the way the sun rays differentially 'hit' the earth's surface at the different latitudes as a result of the spherical nature of the earth. The higher the latitudes, the sun rays 'hit' the earth at a more oblique angle and cover a larger surface area (hence lower density). This is why the equatorial regions are the warmest because the sun rays 'hit' more or less at right angle and therefore more sun rays hit per surface area (high density).

The best answer is D. Facilitated diffusion is a channel mediated diffusion and functions much like a bridge over a river that must raise and lower in order to allow boats to pass. When the bridge is lowered, boats cannot pass to the other side of the river. In a similar manner, a gated channel often remains closed, not allowing substances into the cell until it receives a signal (like the binding of an ion) to open. When this signal is received, the bridge (gate) opens, allowing the boats (substance) to pass through the bridge and into the other side of the river (cell membrane)