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.
Most commonly Focus Groups are used when a new product or service is being developed and the company is not sure how the public will react. In this instance, a Focus Group is conducted to get opinions, ideas, suggestions, and reactions before the product or service is available to the public.