A. prevent cross-contamination.
Hormones are chemical substances that help to regulate processes in the body. Hormones are secreted by glands and travel to their target organs in the bloodstream. Hormones can be used to control human fertility.
It will all make more sense if you start from the beginning of the sequence with the structure of DNA. You will remember that messenger RNA contains a sequence of bases which, read three at a time, code for the amino acids used to make protein chains. Each of the sets of three bases is known as a codon.
An atom of chlorine has several valence electrons in its