These two forces are called action and reaction forces and are the subject of Newton's third law of motion. Formally stated, Newton's third law is: For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. So... Newton's third law would be the correct answer.
The answer is: A compound can be separated by physical means.
Length of the sheet is given as

width of the sheet is given as

now let say its thickness is "t"
so the volume of the sheet is given as



mass of the sheet is given as

now we have


by solving above we have

so the thickness of sheet will be above
-- "Declination zero" means the object is in the sky at some point directly over the Earth's equator.
-- If it's the sun and it appears to be over the equator, then that tells us that the Earth's axis is not tilted toward or away from it.
-- That in turn tells us that the Earth is at one of the two equinoxes in its orbit, either the Spring one or the Autumn one. <em> (D)</em>
-- (The first days of Summer and Winter coincide with solstices, not equinoxes.)