Antibodies fall into five classes. Which class makes up roughly 80 percent of all antibodies?

1. Antibodies can be divided into five classes: IgM, IgG, IgA, IgD, and IgE. 2. IgGs make up about 80 percent of all antibodies. 3. Their heavy chains consist of one variable domain and three identical constant domains. 4. IgM makes up about 10 percent of antibodies, IgA is concentrated in secretions like saliva and tears, and IgE is present in only small quantities, none matching the 80 percent figure given for IgG. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 42 "The Immune System", section Antibody Classes_