Which is better raw or synthetic materials , and why.

If there is some reason you cannot get the compound from a natural source, it may be helpful to use a synthetic, yet identical, version. If harvesting the item from nature is too expensive or over-harvesting could damage the environment or destroy habitat, it might be better to synthesize the compound.

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.