It's is used by putting the lager chromosomes on the bottom and the smaller ones on the top so when they get DNA sample of something they can she if some thing is closely related or not
<u>Answer:</u>
Natural: mountains, rocks, soils, ecosystems, etc.
Manmade: artificial streams or tributaries, roads, farms, etc.
<u>Explanation:</u>
A watershed a geographical area that drains all forms of surface water (rainfall or snowmelt) from <u>higher altitudes</u> (e.g. top of mountains) to the <u>lower altitude</u> (e.g. rivers) thus draining the water to the same place.
Since watershed is a large area, it often comprises both natural and manmade features. Manmade features are typically the roads or (small) cities that are developed by humans in the hilly areas. On the other hand, natural features are developed due to the natural action of hydrogeological and/or meteorological conditions over the course of longer time periods.
It is important because it allows us to understand many things such as natural selection and genes passed down through generations. It also helps us solve biological problems that impact our lives.