Knock, knock. Who’s there? Cow says. Cow says who? No, a cow says moo!

What did one cell say to its sister cell that stepped on its toe? “Mitosis!”

I asked my wife what she wanted for her birthday. She said, “Nothing would make me happier than a diamond ring.” So I got her nothing.

Why did the germ cross the microscope? To get to the other slide.

Knock, knock. Who’s there? Boo. Boo who? Aw, don’t cry, it’s just a joke!

Why are chemists great at solving problems? Because they have all the solutions.

My wife told me to stop acting like a flamingo. So I had to put my foot down.

Why can’t you trust an atom? Because they make up everything.

Knock, knock. Who’s there? Lettuce. Lettuce who? Lettuce in, it’s cold out here!