Answer:
When you eat, food passes from the throat to the stomach through the esophagus. A ring of muscle fibers in the lower esophagus prevents swallowed food from moving back up. These muscle fibers are called the lower esophageal sphincter
Explanation:
I am not 100% sure but I thinking it responds when pathogens enter the body because the immune system is meant to protect your body from illness.
Answer:
2 plates
2 plates on connected to the african plate they tend to pull away time to time
