This era, the age of mammals, represents less than 1 percent of geologic time
It's defined as a form of an element with the same atomic number but different atomic weight
Named for an English scientist, it's a division of classical physics
When burning, sulfur becomes this compound that's used to keep dried fruit from turning brown
An American, Theodore Maiman, built the first of these light-amplifying devices in 1960
A compass points toward this north pole
In computerese, a "vaccine" is a program that seeks out & destroys these
The most abundant metal on Earth, when it was discovered in 1820 it was worth more than gold
Varieties of these simple plants include red, brown, green & blue-green
Behaviorists & dogs drool over the work of this Russian physiologist