Which of the following statements is incorrect? the esophagus produces digestive enzymes. the esophageal mucosa consists of nonkeratinized stratified squamous epithelium. at each end of the esophagus, the muscularis forms two sphincters the upper esophageal sphincter and the lower esophageal sphincter. the upper esophageal sphincter consists of skeletal muscle and the lower of smooth muscle. the esophagus secretes mucus and transports food to the stomach.

The incorrect statement is: the esophagus produces digestive enzymes.

The esophagus is a fibromuscular pipe organ for the food transport from the pharynx to the stomach. The food passes through the esophagus via peristaltic contractions (rhyttmic contractions of the smooth muscles that propagate in a wave down the pipe). The esophagus is one of the first components of the digestive system and the gastrointestinal tract that is involved in the process of swallowing.

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%

a symbiotic relationship with the mitochondria