D. Fossil fuels are the remnants of organisms that lived a long time ago and were buried, heated, and formed into hydrocarbons.
B. Two protons and two neutrons
Understanding density helps you predict whether an object will sink or float.
C
The answer is most likely the last option.
Explanation:
When you breathe in, or inhale, your diaphragm contracts and moves downward. This increases the space in your chest cavity, and your lungs expand into it. The muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale