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.
Wherever you focus your attention, your eyes and your mind establish clean, crisp edges that define the object within itâs environment. In painting, however, it is up to us as the artist to establish what is the focus point. The focus point is established first through composition.