The following links provide some great resources that YOU may find helpful whether with homework or to satisfy your curiousity.
Teens Health provides a host of information for both boys and girls about health, fitness, hygiene and much more that you may find useful.
FactMonster offers help for an array of subjects such as math (fractions/coversions/formulas), geography/history (maps, country facts, world religions), science (human body, chemistry, physics), and much more.