Nitrogen is a light gas that find application in my areas including being used to keep things cold.It has a freezing point of -210°c so the scientist Nitrogen in the question at 100°c have already freezed and no longer a liquid.
At the end of each organ system you will need to make a summary of that ... So how does the food we eat eventually get to our cells in a small enough form ... The circulatory system is responsible for transporting blood with oxygen (O2) ... the digestive system to the cells in the body and remove waste products to be excreted.
It has a 1:2 ratio If you look at the start of PbO2 it does not have a number so that is the one and if you look at 2H2O that has a 2 in front so that is where you get the 1:2 ratio