Final answer:
The most popular system for classifying climate in different regions on Earth is the Köppen-Geiger climate classification system. Type C climates, also known as moderate or temperate climates, are the most favorable for human habitation and have the largest human population densities on Earth.
Step-by-step explanation:
The most popular system for classifying climate in different regions on Earth is the Köppen-Geiger climate classification system. This system was developed by Wladimir Köppen, a Russian German climatologist, in 1884. The Köppen-Geiger system categorizes climate types into six basic types: A, B, C, D, E, and H.
Type C climates, also known as moderate or temperate climates, are the most favorable for human habitation and have the largest human population densities on Earth. They are found mostly in the mid-latitudes bordering the tropics, with distinct winters and summers. In the United States, C climates dominate the southeast and the West Coast.