I believe that the correct answer to this question would be "produced with the help of <span>ecosystem-based management". Books are often made out of trees, and in order to produce paper, ecosystem-based management is needed.</span>
<span>Downcutting (also known as rejuvenation) of a stream may be due to the uplift of land. It is a process by the action of the hydraulic that makes the channel of the valley or stream by simply get rid of any material on the floor of valleys and streams. Downcutting speed is determined by the base level of the stream. It is the lowermost point that a valley or streams can lose.</span>
Tropical places are hot because the humidity coming from the moisture of the plants and water are heated by the sun on the top layer of the tropical zone. The climate varies little in rain forest. There are five layers in the tropic trees so it's so thick that barely any light come through. This is also why vines grow up the trees so they can reach the sunlight to get nutrients. Also, the tropics are near the equator and that also causes the heat. The polars are cold because they barely get any sun heat to melt the snow or warm it up. The polars are melting due to certain chemicals and gasses in the atmosphere. also known as global warming. Hope that was helpful!