If a product contains bleach (peroxide), it will whiten your teeth. But not all treatments are created equal. It's the concentration or percent of hydrogen peroxide a teeth-whitening system contains and the amount of time it's in contact with your teeth that determines its effectiveness.
Definition of fecund - producing or capable of producing an abundance of offspring or new growth; highly fertile Definition of fecund - producing or capable of producing an abundance of offspring or new growth; highly fertile
See unfettered defined for English-language learners. A fetter is a chain or shackle for the feet (as on a prisoner), or, more broadly, anything that confines or restrains. The word derives from Middle English feter and shares a relationship with Old English fot, meaning foot..