Nyctalopia
Nyctalopia is the condition of night blindness characterized
by inability to see clearly at night or in dim light and the ability to see
clearly in the day. Deficiency of vitamin A leads to nyctalopia. Other possible
causes of Nyctalopia include myopia, cataract, retinitis pigmentosa and some glaucoma
medications.
<span>Lay the frog on its back, spread out its limbs, and pin them to the tray. Use forceps to lift the skin between the hind legs and make a small incision with a scalpel. Continue the cut up the center of the frog's body with scissors, being careful to cut through the skin only. Use forceps to hold the skin away from the muscle while you cut, if necessary. Make horizontal incisions just above the legs and just below the arms, then fold the resulting flaps back and pin them. (You may need to use a scalpel to help separate the skin from the muscle underneath as you fold it back.)Repeat the incisions as before, this time cutting through the muscle layer to a point just below the arms. Lift the muscle with the forceps to prevent cutting the organs underneath.When you reach the area just below the arms, turn your scissors and make horizontal cuts through the hard sternum. Repeat the horizontal cuts just above the arms, and then remove the bony strips entirely. Pin the remaining muscle flaps back, just as with the skin.<span>Look into the body cavity. The yellow finger-like projections on the sides are the fat bodies. It may be necessary to remove some of these in order to see the organs clearly. Likewise, a female specimen may have well-developed eggs filling the body cavity and obscuring the organs. Remove them as necessary.</span></span>
A large deposit of sand and soil formed at the end of a river is a delta. When a river empties into the ocean, the current carrying smaller particles, such as soil and sand, slows down and eventually stops, causing these particles to be dropped off on the shore. This eventually leads to a triangular deposit, usually referred to as the mouth of the river.
During a lunar eclipse, the Earth gets in between the sun and the moon
