The answer is the plant growth, because the dependent variable is what responds to the independent variable.
The branch of biology dealing with interactions along organisms and between organisms and their environment is called Ecology, I believe.
Pretty sure the answer is oxygen, as it is produced in photosynthesis and consumed in respiration.
Oceanic crust<span>tends to be denser and thinner than </span>continental crust<span>, so the denser </span>oceanic crust<span> gets bent and pulled under, or subducted, beneath the lighter and thicker </span>continental crust<span>. This forms what is called a subduction zone. The answer is B.</span>