Answer:
D the train
Explanation:
The train is safe very fast and was the first built
Alpha helices and Beta pleated sheets make up the secondary structure of protein.
When you swallow food, it doesn't just drop down into your stomach. Muscles contract in a wave-like motion to move the food along through the esophagus. This muscle movement is called, peristalsis, or peristaltic waves. These peristaltic waves contract behind the food bolus pushing it along the digestive tract.
The genetic drift is a major factor in evolution when there is lower gene flow
