Answer:
A
Explanation:
does it occur naturally on Earth
Answer:
As the cloud shrinks in size, its central temperature increases, as a result of its gravitational potential energy being converted to thermal energy.
We are assuming that the mentioned cloud, is a cloud of interstellar dust (nebula), in which this definition is applicable. Since energy cannot disappear, the lost gravitational potential energy would have to transform into something else, in this case, thermal energy, or simply heat, which will increase the overall temperature of the cloud.
There's lots of resources that the Amazon rainforest provides to the people around the world, of which the most important ones are:
- Fresh water; it contains around 20% of the world's fresh water.
- Oxygen; it is the biggest producer of oxygen on the planet.
- Food; healthy food distributed all over the world.
- Medicinal plants; thousands of plants that can cure and prevent most of the known diseases.
- Minerals; gold, copper, silver, zinc, tin...
