Why can sharks swim quickly through water

The reason why sharks can swim fast is that unlike most fish, sharks have tails that are not horizontally symmetrical . Instead , the top of a shark's tail protrudes further  back than the bottom , giving the shark  lift while swimming and making it "spring" forward at speed.

Most fish make a single water "ring"  that moves backward at the end of their tail's stroke but sharks are thought to produce two rings because of their asymmetrical  tail which bespeaks a more efficient propelling action.

It has also been discovered that sharks can raise the tiny teeth-like structures called placoid scales on their skin to create tiny wells across the surface of their skin  which reduces drag just like the dimples on a golf ball, thus enabling the shark move forward faster.

the transfer of energy between two molecules spaced just nanometers apart plays a key role in many technologies, including photovoltaics, quantum information systems, lighting, and sensors, as well as in biophysics to measure nanometer distances and in photosynthesis. but an open question in this area is what effect, if any, the surrounding photonic environment has on this nanoscale energy transfer. by designing and performing a carefully controlled experiment to answer this question, scientists have settled the debate and found clues to improving the efficiency of many of the technologies that rely on this process.

explanation: