First turn 18% to a decimal, which is .18, then multiply it by 450.
450 x .18 = 81
The CN tower is the tallest freestanding structure in the Western Hemisphere.
Since you did not give options, I will just help you out by saying that Implied Powers are powers that are <em>Not stated directly but are suggested to be true</em>
I guess the answer is NO-3.
Hydrogen is used by plants which combine it with carbon during the photosynthesis process and release oxygen into the atmosphere which is used by all living beings.