Oxygen and Carbon Dioxide are the two gases being exchanged in the alveoli. Carbon Dioxide diffuses blood into the air, and oxygen diffuses from the air in the alveoli into the blood.
Both answers C and D are correct, however, answer D makes more sense.
The right answer for the question that is being asked and shown above is that: "The hydrilla is an invasive species, and its presence will have an overall negative effect on the estuary." This is the statement that<span> is true of the hydrilla growing in the Hudson River Estuary.</span>