Proteins are organic compounds that consist of carbon, hydrogen, oxygen, nitrogen, and, in some cases, sulfur. They are made up of repeating units called amino acids. They provide cells with energy, form tissues, speed up chemical reactions throughout the body, and perform many other cellular functions.
<span>What MUST occur before mitosis and meiosis can occur is B) DNA replication. DNA replication is a process of copying DNA into an identical copy. Before mitosis, the genetic material of the mother cell must duplicate so that each daughter cell have the same amount as the mother cell. On the other hand, meiosis is a reductive division. But meiosis II is similar to mitosis, so DNA replication is also necessary.</span>
