Here's why:

* The Earth's Tilt: The Earth is tilted on its axis at approximately 23.5 degrees. This tilt causes different parts of the Earth to receive varying amounts of direct sunlight throughout the year.

* The Tropics: The tropics are the regions between the Tropic of Cancer (23.5 degrees North) and the Tropic of Capricorn (23.5 degrees South). The Sun's rays hit these areas at the most direct angle, resulting in the strongest sunlight and warmest temperatures.

It's important to note that the amount of direct sunlight received in the tropics can vary slightly depending on the time of year and the specific location within the tropics. However, overall, the tropics experience the most direct sunlight throughout the year.