Answer:
Antibodies help you immune system.
Answer:
The esophagus and the stomach.
Explanation:
There are many parts to the digestive system, but these are the most common answers.
Pre-Cambrian Era. Earth formed and became a planet 600-3,300 million years ago.
Paleozoic Era. Ancient life. Volcanoes and mount formed.
Mesozoic Era. Middle life (Industrial Ages, Evolution of human technology)
Cenozoic Era. Present life