The biome is the driest. Common floras are cacti, and faunas are snakes and lizards.

B. desert

Explanation:

desert is the obvious....but, y'all know how tests work... If ody ssey, it's in lesson 9 Ecosystems and Biomes. Pass Biomes, to Types of Biomes and there is a chart of all 6. where it states next to desert 3rd bullet point under description "driest biome", under Row Plants and Animals first bullet point cacti, small bushes, short grasses.  Second bullet point has snakes, lizards, mice.  this is what the test wants

the answer to your question is tooth decay.