What are the microscopic air sacs that exchange oxygen and carbon dioxide through the processes of inspiration and expiration?

Proprietary drugs are those that:

a. have a generic name. b. are patented by the original manufacturer. c. have a chemical name. d. are not yet approved by the FDA.

What size does lumber need to be in order to meet the criteria of large-dimensioned?

A. Larger than 2 inches B. Larger than 4 inches C. Larger than 6 inches D. Larger than 8 inches