What is the name of the cosmic coincidence, when the sun, moon, and earth are perfectly aligned, can scientists get a better look at the sun?

When the Sun is eclipsed by the Moon this Sunday, for many observers across much of the world it will be temporarily replaced by a beautiful ring of fire - a brilliant annulus of stellar plasma just peeking out around the dark lunar disk. This doesn't always happen, partial solar eclipses merely trim away a chunk of the solar disk, and true total eclipses perfectly blank out the visible surface of the Sun. It's all a matter of alignment between Sun-Moon-Earth and our mutual orbital gymnastics.

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation: