Maëlle, 7, wants to know why some shells are smooth, while others are corrugated. It turns out that while corrugated shells are strong, smooth shells can move fast.
Cats evolved in hot desert regions where there were lots of small animals to eat. So they evolved feet that are perfect for pouncing on prey, climbing, scratching and jumping from great heights.
People used to think that when they looked up at the night sky, they were seeing all of space. Then American astronomer Edwin Hubble found out something so amazing, NASA named a telescope after him.