Chemical
From Tardis Wiki, the free Doctor Who reference
A chemical was a type of substance that could do several things.
By 2007, a sign in a Deffry Vale High School classroom warned of "Dangerous chemicals" within a cupboard. (TV: School Reunion)
The 456 found that human children produced chemicals which felt "good". (TV: Children of Earth: Day Five)
Mia Bennett proved that Earth plant life could grow on Martian soil with the help of chemicals. (TV: The Waters of Mars)
