Use what you know about atmospheric circulation and seasonal changes in the sun’s orientation to earth to explain the highly seasonal rainfall in the tropical dry forest and tropical savanna biomes. (hint: why does the rainy season in these biomes come during the warmer months? )

The Inter-Tropical Convergence Zone (ITCZ)region gets the most direct sunlight at any given period in time. This in turn causes air to be unstable with a drop in pressure and rise of air which cools and condenses into clouds to form precipitation causing the wet season in the tropics.

In this region, the sun is directly or almost overhead as seen during summer periods in the tropics.

Only in areas of the North and South of the ITCZ known as doldrums which at times are parallel to the ITCZ do we have high pressure that aren't conducive to precipitation causing dry season in the tropics.

In the ITCZ zone, we also have the tropical rain forests along the equator with huge amount of all round rain for the year.

Along the equator, on either side of the rain forests we have the dry and wet forests with the savannah to the North of this region and the southern hemisphere to the south of these forests since these forests are seen mostly in the ITCZ than the savannahs.

Rain shadows and ocean cueeebts may at times cause some savannahs to be along the equator and some rain forests -wet and dry forests- to be positioned further form the equator.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.