If a system stores kinetic energy, which choice must be true?

1. the molecules, atoms, and/or subatomic particles must be exerting forces on each.
2. the molecules, atoms, and/or subatomic particles must be at rest.
3. the molecules, atoms, and/or subatomic particles must be within earth’s gravitational field.
4. the molecules, atoms, and/or subatomic particles must be moving.

4. The molecules, atoms, and/or subatomic particles must be moving.

Explanation:

The only answer can be considered to be true is 4.

The answer 1 refers to elastic potential energy and answer 2 refers to gravitational potential energy.

If a body to store kinetic energy then as the word 'Kinetic' suggest the object should store the energy in form of motion. So only  answer that can be considered is 4.

Option 4: The molecules, atoms, and/or subatomic particles must be moving.

Explanation: Kinetic energy is the energy related to the movement, and is described by the equation:

K = m/2*v^2

where m is the mass of the object and v is the velocity of the object.

Then, if a system is storing kinetic energy, this means that the molecules, atoms and subatomic particles must have a velocity, this means that they are moving, then the correct option is the fourth one.

explanation:

areas w steep slopes, west coast, rocky mountains, and appalachian mountains

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.