It can be a compound or a single element. An element is a pure substance that cannot be separated into simpler substances by chemical or physical means. There are about 117 elements, butcarbon, hydrogen, nitrogen and oxygen are only a few that make up the largest portion of Earth.
I would say d.
1.54 I think... if that isn't correct you should use Google, a study guide, or a calculator
Answer:
Chemical change
Explanation:
The rusting of iron/a nail is a chemical change
Iron (Fe) and Oxygen (O) combine to create the compound Iron Oxide (Fe2O3), which is rust.
Answer:

Explanation:
We know that the speed of light is equal to 
We need to find how far the light travel in 3 days.
Speed of an object is equal to distance covered divided by time taken.
Also, 1 day = 86400 s
3 days = 259200 s
So,


So, the light will travel
in 3 days.