The sun is best described as

The sun is described as a big star composed mainly of hot hydrogen and helium gas.

There are various layers in the Sun, including the core or core, the radiative zone, the convection zone, the photosphere (which emits most of the sunlight), the chromosphere and its outer part, the corona. Density decreases with altitude, from the nucleus to the atmosphere. The temperature in the nucleus is of the order of 15 million kelvin.

The solar atmosphere is a complex medium consisting of plasma subjected to an intense magnetic field, with solar flares and the solar wind. Sunspots, which appear dark because of their lower temperature, are, like the crown, radiosources. Solar activity related to these phenomena varies cyclically.

The observation of the solar spectrum is carried out thanks to spectroheliographs. This spectrum includes rays, known since Fraunhofer (1814), which signal the presence of hydrogen and helium mainly and about sixty other elements. It also includes bands that betray the presence of molecules in the solar atmosphere.

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:

answer: c.

explanation: