Answer:it is 3 just look at the middle numbers
Explanation:
Outdoor pollution primarily results from the combustion of fossil fuels by industrial plants and vehicles. This releases carbon monoxide, sulfur dioxide, particulate matter, nitrogen oxides, hydrocarbons and other pollutants.
1. 5 electrons.

- Therefore, the 3d subshells blanks will be like this:
- ↑ ↑ ↑ ↑ ↑
2. 6 electrons.

- The 3d subshells blanks will be:
- ↑↓ ↑ ↑ ↑ ↑
3. 7 electrons.

- The 3d subshells blanks will be:
- ↑↓ ↑↓ ↑ ↑ ↑
Hope you could understand.
If you have any query, feel free to ask.
Answer:
Explanation:the best guess I will go with is H but I might be wrong
Answer:
The SI system , also called theatrics system, is used around the world