If the poreis completely closed to the surface, the result is a whitehead. If the pore is wide open, oil becomes oxidized (that is, acted on by oxygen in the air), the oil changes from white to black, and the result is a blackhead. This is how the two types of comedones develop. Comedo is the Latin word for glutton.
The Amazon rainforest topical climate. Tropical climate refers to zones in a range of latitudes between 5/10 to 35. The temperatures remain high all over the year and shows an annual wide change in precipitations with wet and dry seasons: The dry season duration is proportional to the latitude to ultimatly become a mostly dry area.
World map with the intertropical zone highlighted in crimson. Tropical climate zones of the Earth where all twelve months have mean temperatures above 18.0 Â°C (64.4 Â°F) The tropics are a region of the Earth surrounding the equator.