Answer:
solar radiation strikes the poles at a lower angle and travels through more atmosphere.
Step-by-step explanation:
In Science, Earth's polar regions refer to the areas that are typically located between the North Pole and the Artic Circles or South Pole and the Antarctic Circles.
The very cold temperatures found in polar regions causes the air to be very dry and as such there's no much atmospheric moisture; reducing the amount of precipitation (rain, sleet, snow or clouds) drastically.
At higher altitudes (heights above sea level), the angle of incidence of the sun's ray (sunlight) is usually at a low angle striking the tilted surface of the Earth.
Hence, the main reason polar regions are cooler than the equator is that solar radiation (sunlight) strikes the poles at a lower angle and travels through more atmosphere.