LiCl, because lithium (Li) has one positively charged ion (1+), and
chloride (Cl) has one negatively charged ion (1-), so they
cancel each other out.
A valve is a flap of tissue that prevents blood from flowing back
Researchers found the "cosmic microwave background radiation", which is a heat imprint left over from the big bang.
The redshift of light emitted by most galaxies indicates the universe is expanding.
