The less dense the air is, the less
and other gases are available for respiration

Theoretically, which metal should be the most reactive? hydrogen lithium francium fluorine

There is one girl i like and i don't know how to tell her that, i have a feeling she knows but if she doesn't i don't want to make a fool out of myself how is one way to boost my confidence on asking her out

What human activity increases beach erosion?