Final answer:
The correct term for the lining of a beef stomach is honeycomb, which is the reticulum with a honeycomb-like texture. For the question about body cavities, mucosa is the lining that covers body cavities exposed to the external environment.
Step-by-step explanation:
The lining of the beef stomach that is mentioned in the question is known as honeycomb. This term refers to one of the four chambers of a cow's stomach, specifically the reticulum, which has a texture resembling a honeycomb. The other options provided, such as blanket, leather, and suede, do not correctly describe the lining of a beef stomach.
In regards to the other biological question presented, the lining that covers body cavities exposed to the external environment is the mucosa. This lining is found throughout various parts of the body such as the digestive, respiratory, and urogenital tracts, providing protection and also facilitating absorption and secretion.