User: The greenhouse effect is a result of A. absorption and radiation of energy in the hydrosphere. B. consumption of fruits and vegetables that produce a biofuel. C. absorption and radiation of energy in the atmosphere.
A principal focus or focal point is a special focus: 1  For a lens, or a spherical or parabolic mirror, it is a point onto which collimated light parallel to the axis is focused. Since light can pass through a lens in either direction, a lens has two focal pointsâone on each side.
stress, focus(noun) special emphasis attached to something. the stress was more on accuracy than on speed. focus, focal point(noun) a point of convergence of light (or other radiation) or a point from which it diverges. focus(verb) a fixed reference point on the concave side of a conic section. concentrate, focus, center, centre, pore, rivet(verb) direct one's attention on something.