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.
Think of two points A and B. A is where you are and B is your goal. When you are goal oriented, everything that you do revolves around getting to point B. Point A is simply the place where you put in the work. Point B acts as the North Star in guiding all your actions.