Is fiberglass a "single compound" or a "mixture of compounds"?

Gwhich r group would most likely be found in a hydrophobic area of the tertiary structure of a globular protein? which r group would most likely be found in a hydrophobic area of the tertiary structure of a globular protein? −ch2−oh −ch2−o||c−nh2 −ch2−coo− −ch2−ch2−ch2−ch2−n+h3