You have to do a report :
So
the truck efficiency is 38%.
Answer:
B.) Oxygen is usually -2
Explanation:
Hydrogen is usually +1.
A pure group 1 element is not always +1.
A monoatomic ion can be a range of numbers. However, it must be a charge other than 0.
The air in the sky and the clouds are gas, however some things in the sky [such as the sun/moon] are solid.
Hope that helped!