In the punctuated equalibrium model of evolution, periods of evolution are:
A) Short, with rapid change
B) long with rapid change
C) long with gradual change
D) Short with gradual change

The pharynx is the structure in the body that serves as a pathway of both air and food. how does the body make sure that food does not get into the lungs? the salivary glands secrete enzymes that pull food out of the air pathway. the small intestine pushes the air out of the digestive system. the pancreas breaks down food in the air pathway. the epiglottis closes the air pathway so that food will not enter it.

Several billion years ago which gas was the least prevailant in the atmosphere

The earth formed roughly 4.5 billion years ago, yet evidence of life dates back to about 3.5 billion years ago. which one is not a possible hypothesis of how life on earth arose?