Answer:
A.Testable hypotheses
it makes the most sense out of the rest
Answer:
The ability to bring water into the gills when the mouth is closed would benefit a bottom dwelling shark or ray, because it would allow them to be more discreet when in the process of catching prey and they would be able to stop swimming. Most sharks have to continuously swim or else they would sink, while being able to bring water into the gills when the mouth is closed would highly benefit them and allow them to stop swimming for a moment.
Explanation:
I am not 100% sure this is the correct answer, but I am currently doing a lab on this, so I am using the knowledge I previously had and online resources. I am pretty confident though.
... During this process, plants cleave the carbon from the two oxygen molecules and release the oxygen back into the surrounding environment. Plants are thus primarily responsible for the presence of atmospheric oxygen.
PLS REPHRASE a bit SO YOU DONT GET BUSTED FOR PLAGIARISM