Some rivers begin in mountains or hills, where rain water or snowmelt collects and forms small channels, . At first, the channels are small and are called rills. As more water enters the channels they grow forming gullies (larger channels). The streams in the gullies eventually become big enough to form a river
Mutations and natural selection cause adaptations. Mutations can cause instant adaptations, while natural selection is the process by which adaptations occurs over a series of generations.
Adaptations are changes or processes of changes by which an organism or species becomes better suited for its environment.
False.
All sources of pollution do not come from human activities.
<h3>What are the causes of pollution?</h3>
There are some natural causes of pollution. When dangerous pollutants enter the air as gases, liquids, or solids, air pollution is formed. Although there are some natural processes that can produce air pollution, such as sulfur and chlorine gases from volcanic activity, smoke and ash from wildfires, dust storms, and biological degradation, manmade sources account for the majority of pollution in the atmosphere.
Burning fossil fuels for transportation, energy, and industry produces the majority of air pollution that is caused by humans. Carbon dioxide, nitrogen oxides, sulfur dioxide, volatile organic compounds (VOCs), and particulates are typical pollutants released by fossil fuel-burning engines. In addition to particles, carbon monoxide and carbon dioxide are produced by stoves, incinerators, and open burning.
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Answer:
Relationship Between Diameter and Circumference
If you know a circle's diameter, you can calculate its circumference with this equation: Circumference = diameter times pi (3.14).
So you know that there are 3,000,000 of bacteria in one gram of soil so you multiply 3,000,000×10 and you get 30,000,000. Then you just check all your options. So it's 3×10^7.
