This is FALSE, because banning candles with lead cores would be an effective way to prevent lead poisoning. Other things that can be done to prevent lead poisoning are banning stuffs like lead glazing on ceramic dishes, and the use of lead solder. It would also be effective to phase out waste incineration.
However, banning the use of led pencils in schools <span>would be ineffective to prevent lead poisoning.</span>
Reduce constipation, control blood sugar, and reduce cholesterol
The correct answer should be gymnastics. While the other mentioned sports could help him too, gymnastics is the most comprehensive one because it involves almost every muscle in the body to do various exercises, whereas biking would increase his leg muscle fitness most, but would not do much for the rest of his body.