From the anterior vena cava,blood flows to the right atrium.
Red tide is an explosive growth of the <span>dinoflagellates bacteria. </span>
The actual answer is, "A", an ocean trench.
You can find out more about them by researching them up on Google, it's only a few phrases and a hit on the enter key :P
Answer:
cellular respiration...that's breathing out of humans
and through human activities like burning of fossil fuels...