Here's a simple - and cute - worm colouring page for your youngest children...
Worm Colouring Page
Each colouring page in this set of 6 has a different phase of a frog's life cycle to colour in, and if you choose the blank versions you can label each stage too.
My son rescued some tadpoles last year and watched them develop into frogs, and the whole process was fascinating! You can learn more about the life cycle of a frog from this simple colouring page. Choose two versions below: labelled, or blank for you to label yourself.