The difference between protons and neutrons are that one has a positive charge and one has a neutral charge. The similarities between the two is that they both make up an atom. The Electrons in an atom are in orbit of the cell inside the Electron cloud and is kept in the cloud by electromagnetic force.
ANSWER:
D
EXPLANATION:
Both of their temperatures stay about the same throughout the experiment.
Answer:
The return of blood to the heart is assisted by the action of the skeletal- muscle pump. As muscles move, they squeeze the veins running through them. Veins contain a series of one-way valves, and they are squeezed, blood is pushed through the valves, which then close to prevent backflow.
D. He controlled variables by studying one or two traits at a time
