A、Changing technology. B、A changing limiter. C、Changing genes. D、A changing mindset. B

Good morning, ladies and gentlemen. Many people have no problem telling the Olympic motto— "Faster, Higher, Stronger. " And athletes have fulfilled that motto rapidly. Now we all have this feeling that we’re somehow just getting better as a human race, but it’s not like we’ve evolved into a new species in a century. So what’s going on here? I want to take a look at what’s really behind this march of athletic progress.            
    Throughout sports, technology has changed the face of performance. In 1972, Eddy Merckx set the record for the longest distance cycled in one hour at 30 miles, 3,774 feet. Then that record improved and improved as bicycles improved, until today, 30 miles, 4,657 feet, a grand total of 883 feet farther than Eddy Merckx cycled about four decades ago. Essentially the entire improvement in this record is due to technology.
    Still, technology isn’t the only thing pushing athletes forward. While indeed we haven’t evolved into a new species in a century, the gene pool within competitive sports most certainly has changed. In the early half of the 20th century, physical education instructors and coaches had the idea that the average body type was the best for all athletic endeavors: medium height, medium weight, no matter the sport. But that idea started to fade away as sports scientists and coaches realized that highly specialized bodies fit into certain athletic types. And athletes’ bodies became more different from one another.
    Still, even changing technology and the changing gene pool in sports don’t account for all of the changes in performance. Athletes have a different mindset than they once did. Our brain acts as a limiter, preventing us from accessing all of our physical resources, because we might hurt ourselves, tearing our muscles. But the more we learn about how that limiter functions, the more we learn how we can push it back just a bit, in some cases by convincing the brain that the body won’t be in mortal danger by pushing harder. Changing technology, changing genes, and a changing mindset have cooperated to make athletes stronger, faster, bolder and better than ever.
    Thank you very much.   
    Questions 23 to 25 are based on the recording you have just heard.
    23.Which of the following is TRUE?     
    24.What did sports scientists and coaches realize?
    25.Which is NOT a factor mentioned by the speaker pushing athletes forward?