What does the word 'menarche' refer to?

Your internet settings won't let you play MightyQuiz. :(

But... we've got a solution!

• 1) Turn on cookies in your browser.
• 2) Reload the page.
• 3) Play! :)

Your internet settings won't let you play on Everyday Scientist. :(

But... we've got a solution! :)

You can play in a new window here. Easy!