C.
The skeletal system provides structure to the human body.
Democritus is a Greek theorist that believes that atom is the smallest part of the substance. Atom, as he defined, is an indivisible entity. Leuccipus was Democritus' teacher who also believed on that notion. All matter are made up of atoms. If atoms are intact, the property of the substance is firm and solid while if the atoms are much apart, it would be described as a gas. Aristotle had a different belief of matter. He believed that the composing entities of matter are the four elements. However, this notion was rejected and proven through scientific inquiries about atoms and subatomic particles
Firstly, we need to know what a healthy ecosystem is. When an ecosystem is healthy, this would mean that it could supply all the resources that all organisms present in it and with all the resources, there is diversity. Old growth forests are considered healthy because of this reason. These forests remain untouched and had remained in providing the resources needed for the organisms present in it.
