Muscles
20 Mar 2008Muscles have an important role in our bodies! Muscles help you do lots of things, such as blink an eye, swallow, and digest your food. Muscles also help you breathe, lift an arm, take a step, and even...
The German physicist Johann Wilhelm Ritter, in 1801, found that there exist invisible rays beyond the violet end of the visible spectrum of the Sun that darken silver chloride even more efficiently th...