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.
The tropical climate is then a place of warm low pressures. This is where you find the rain forest belt around the earth. The subtropical climate is then the belt around the earth where you find warm but dry air because it sinks.Those are the high pressures are roughly latitudes 30. That is where you find most deserts around the earth. The front at latitude 60 is then the front between polar and subtropical air masses.The latter climbs over the former because warmer and the process decreases the pressure thus forming low pressures.hat is where you find most deserts around the earth. The front at latitude 60 is then the front between polar and subtropical air masses. The latter climbs over the former because warmer and the process decreases the pressure thus forming low pressures.