7 protons. As well as in nitrogen-14. The difference between nitrogen-14 and nitrogen-15 is in a number of neutrons. In nitrogen-14 - 7 neutrons, in nitrogen-15 - 8 neutrons.
It's letter C. When ever you read "breaks down" always think decomposition. When you read that compound get together to form "a single" compound, think synthesis.
Resistance of a material being scratched in known as: Hardness
The most likely answer is the boiling point and freezing point of water. The Celsius scale starts at the freezing point of water (0°C) and than scaled so that 100°C fell on the boiling point of water.
I hope this helps. Let me know if anything is unclear.
The major visible difference between<span> the two are crystal size, </span>intrusive rocks<span> have a larger crystal/grain texture due to the slow cooling of magma below the earth surface which encourages the growth of larger crystals, while </span>extrusive rocks<span>, because of the rapid cooling at/above the earth's surface does the opposite. Hope I helped</span>
