No. they were all joined together and then they separated
B is correct
D is appealing but the electrons spend more time around the oxygen than the hydrogen
Addiction is most likely the answer.
This statement is true. Early land animals indeed had gills as well as lungs. It is generally known that amphibians breathe through their skin, like how the lungs needed the skin for its respiratory. Fish have gills for breathing while mammals do have their nasal cavity and lungs for their gas exchange.
