Cells that are rapidly undergoing mitosis constantly repair and renew the lining of the pharynx and the esophagus, which is particularly vulnerable to abrasion associated with swallowing. which of the following terms best describes this lining?

a. serosa
b. muscularis externa
c. submucosa
d. mucosa

d. mucosa

Explanation:

The pharynx and esophagus possesss all of the basic histological layers of the gastrtointestinal tract (GI tract). The layers are:

mucosa - layer closer to lumen which cocnsists of epithelium, lamina propria and muscularis mucosaesubmucosa-layer of loose connective tissue with vesselsmuscularis propria-layer of inner circular and outer longitudinal muscular layersadventia - layer of  loose connective tissue

The soviet union beat the us to the first successful launch, with the october 4, 1957, orbiting of sputnik 1, and later beat the us to have the first human in earth orbit, yuri gagarin, on april 12, 1961. the "race" peaked with the july 20, 1969, us landing of the first humans on the moon with apollo 11