Answer:
Azimuthal map projections
Explanation:
The Azimuthal map projections come in a circular shape. They represent the whole world but in a different manner than that of the other map projections. The other map projections tend to have problems with the size of the objects as they get further away from the Equator, but this map projection doesn't have that problem. The Azimuthal map projections actually represent all of the places on Earth with their correct distances from the central point, and they all have their sizes correct proportionally to the scale, thus making an accurate map projection.
Plants use their stomata to take in Carbon dioxide and take out oxygen during photosynthesis. It's how they "breathe" if that makes it more understandable.
Boundary between two air masses of different temperatures and/or humidity levels
Answer: a cell
Explanation: a cell is the basics unit of life. It can also be said to be the building block of life. All lifes from the simple procaryotic bacteria to the more specialised eucaryotic humans are made of cells.
Several cells of the same function form tissues. Several tissues of same function form organs. Different organs of the same function form a system. Several system aggregate to form an organism.