Answer:
The correct option is b. lower esophageal sphincter
Explanation:
The esophagus is the initial part of the digestive tract and its function is the transport of the alimentary bolus from the pharynx to the stomach, through the thorax and avoid the reflux thereof. It begins and ends in two sphincter structures, the upper esophageal sphincter and the lower esophageal sphincter, which separate it from the pharynx and stomach. The lower esophageal sphincter has two functions: relax during swallowing and prevent reflux of the gastric contents into the esophagus in the postdeglutory period. After swallowing, there is a relaxation of the lower esophageal sphincter, pressure dropping to levels similar to those of the gastric fundus, which allows the bolus to enter the stomach. This relaxation lasts a few seconds and is followed by a strong contraction that prevents backflow of food.
The person would of died i could be wrong
Answer:
Birds require high levels of oxygen and, therefore, high rates of gas exchange due to flight demands. Avian resting oxygen consumption is high compared to that of mammals and other vertebrates, and this increases even more during the flight.
Explanation:
Compared to mammals, birds have specific adaptations of the respiratory system that result in higher levels of oxygen exchange.
They return nutrients from waste or dead organisms back into the ecosystem to be recycled.
Answer:
If you got a flu shot this year, next year you'll need it again.
Explanation:
This is because the virus changes, usually rendering the previous year's vaccine partly or totally useless. hope this helps you :)
