I believe its your heart if I am not mistaken hope this helps ^^;
The first level of organization are living cells
Answer:
Deep zone, surface zone and transition zone.
Explanation:
Open sea zone is the area of the coastal areas above the sea bed and cover the continental shelf where large Marine organism are present and there is enough sunlight algae organism use to photosynthesize and produce food for the Marine organisms by converting carbondioxide and water into carbohydrates.
The zone stretches from the surface , to the middle and depth of 200 m.
The surface zone is the area where light penetrates most , the transition stretches from the surface zone downward, in this zone light penetrates bit not as much as surface zone and in the deep zone, it stretches from the transition zone downward to a depth of 200 meters and don't have enough light penetration compare to surface and transition.
Mercury, due to it's low gravity it would not be able to hold a very strong atmosphere.
