Either, carbon, hydrogen, nitrogen, oxygen, phosphorus, or sulfur. I would go with carbon because of the photosynthesis and cellular respiration<span />
Trench
A long , narrow depression of the sea floor formed where a subdcting plate sinks into the mantle
Hope you get it!
It's called hypoxemia, it's low levels of oxygen in the blood, to be more specific, it's oxygen loss in your blood from your arteries. It can cause respiratory disorders, and tissue hypoxia, as a result of the blood not providing much oxygen to your body.
I hope I helped :)
