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.
Knowing how to create strong focal points in art is a skill every artist should understand and be able to execute. Focal points refer to the areas of the artwork that demand the viewer's attention. Intelligent placement of focal points can positively affect the overall composition of the artwork.