The Tomb Raiser Zombies and Camel Zombies are pretty tough, so the player needs to upgrade their plants.
Upgrade your plants' level by replaying previous levels. Then upgrade them more with Puzzle Pieces and the Oven in your house.
Drag as many plants as you can onto the lawn. Use other users' plants to have even more power. It is recommended to have high-health plants at the back to prevent Tomb Raiser Zombies from defeating the plants with its skill, and your leader plant at the front if the other plants are not strong enough to withstand Camel Zombies.