One of the four words does not belong with the other three. Which word does not belong? What is it that the others have in common?
1. Green. Yellow, red and blue are primary colors, green is not. 2. December. The other months have only 30 days. 3. Calculus. The others are cloud types. 4. Cabbage. The others are vegetables that grow underground. 5. Shovel. The others have prongs.