Lyrics: They Might Be Giants. Here Comes Science (Amazon.com Exclusive) [CD/DVD]. Cells.

Life is made out of cells
Cells make copies of themselves
And they make copies of themselves
And they make copies of themselves

Different cells have different jobs
But they all have one thing in common

Inside of every cell is a twisted ladder
A recipe for life called DNA
The directions are written out in the ladder's rungs
Where they can be found
In every cell of everything that lives

A cell knows what it has to do
To grow into some moss or a shrew
Algae or a kangaroo, bug or a sunflower
Dwight David Eisenhower, a frog, a fish or you

Cells are small, too small to see
But together they can make a tree

Within the cell there's a tiny spiral staircase
That tells the cell just how it's going to grow
The instructions are spelled out in letters, one on every step
In a language that the cell knows how to read

Inside the cell is a tiny double helix
Another fancy word for DNA
Which could also be a spiral staircase
Which could also be a twisted ladder
Which could also be a spring

Which could also be a spiral staircase
Which could also be a twisted ladder
Or a crazy looking spring, yeah