C. because a color change can occur due to chemicals mixing, but it can also be a physical change because you can see it happen with your eyes.
A greenhouse gas is one that leads to global warming, by the absorption of infra-red radiation re-emitted by the ground. Common greenhouse gases include carbon dioxide and methane. Surprisingly, water vapour (which contains only oxygen and hydrogen) is also a greenhouse gas and can contribute to global warming.
Answer:
D. Protons & Neutrons
Explanation:
Protons and Neutrons are found in the nucleus of the atom, and the electrons orbit the shells.
Answer:
There are Seven periods in the periodic table