D phytoplankton i believe
A frog's lungs don't work that well, but since it's skin is so thin, oxygen and carbon dioxide can pass trough it.
Nonvirulent bacteria can still be transformed into virulent bacteria if it is combined with debris from heat-killed virulent bacteria that is first treated with RNase, protease, or no enzyme because these are important factors for the establishment of virulence and are often required when bacteria modify their genetic record in response to the conflicting or adverse situations.
Answer:
Flatworms and cnidarians
Explanation:
In simple organisms, such as cnidarians and flatworms, every cell in the body is close to the external environment. Their cells are kept moist so that gases diffuse quickly via direct diffusion. Flatworms are small, literally flat worms, which 'breathe' through diffusion across the outer membrane
