D) The speed of a wave slows as it travels at different speed in different media.
The nebular theory describes the formation of the solar system and states that the system began as a gigantic cloud of gas and dust called a nebula which eventually condensed to form the sun, planets and other objects in the solar system. The first fact speaks to the formation of the planets, where gravity pulled larger clumps of material closer to form solid rocky planets closer to the sun and gas giants further out. The second requirement is that a nearby explosion or super nova would have to disturb our nebula to trigger rotation and the eventual formation of the sun. The third requirement/fact is that the planets go around the sun in the same direction. the last fact is that the planets go around the sun within 6 degrees of a common plane. This indicates that the solar system formed from a spinning disk of materials.
Crust sitting on top of Milton rock of the mantle
In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body when decelerating from its current speed to a state of rest.