Answer: Protons
Explanation: Every atom is defined by its protons every element. So if it has 1 proton its hydrogen no matter what. If it has 2 protons its helium no matter what and so on. So if you know the number of protons you know the element.
The atomic number tells you the number of protons that are in the core of a particular element.
Obviously on Earth :p nwm
Abiotic factors are things in an ecosystem that aren't alive.
Here are a few examples of abiotic factors in a rain forest:
1. Sunlight
2. Water
3. Soil
4. Rocks
Hope this helps!