The answer would most likely be C
The second one is the answer
True, there are many vessels serving as a conduit<span> between the lungs and the heart.
The number of the vessel is many because all the carbon dioxide from body need to be released at the lungs. More vessel means more surface area and blood flow rate to do the diffusion of the gas which means increased diffusion rate. This will allow the lung to transfer oxygen and dump carbon dioxide faster.</span>
Answer:
The temperature is staying the same. In the graph when it shows solid/liquid and liquid/gas, the temperature stays the same until it changes. This is because it reached it's melting point/vaporizing point. For example, a solid gets heated up, it then reaches it's melting point but it can't go higher than that because it isn't fully a liquid yet, once it's a liquid it will then continue to rise in temperature.
I don't think I put enough detail into that explanation but I hope this helps your problem.