TOEFL Reading: ETS-TOEFL阅读机经 - 7CKJGH354ZR35NFML$

Paragraph 2 suggests which of the following about the drag faced by aquatic animals? A. The closer an aquatic animal's body density is to the density of the water, the less drag the animal must overcome. B. Aquatic animals that swim on the surface must overcome fewer sources of drag than animals that swim underwater. C. The drag faced by most fish swimming underwater is much greater than previously thought. D. All fish must overcome at least two forces of drag – the drag produced by their own bodies and by the bow wave.