Choose all the answers that apply.

according to newton's second law of motion:

objects at rest will remain at rest unless acted upon by an outside force
mass has an inverse relationship with acceleration
the greater the magnitude of force, the faster the acceleration
acceleration is caused by unbalanced forces
every action has an equal and opposite reaction

The answers aplicable would be

1) The greater magnitude of force, the faster the acceleration.

2) Acceleration is caused by unbalanced forces.

It's the third one and the fourth one that's correct.

d) physical means can be used to separate the components of air.

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.