B. Mitochondria
The mitochondria is where ATP is made, hence why it is often called the "powerhouse" of the cell.
Answer: Energy transfer is the movement of energy from one location to another. Energy transformation is when energy changes from one type to another. While energy can be transferred or transformed, the total energy always remains the same.
They are all freshwater. So the closest would be c. an estuary since it has a free connection with the sea since the sea is not freshwater.
So C.
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