Australia
North America
Antarctica
Asia
The savanna gets a fair amount of rain, at least 20 inches a year.
They have thorns
Ants protect them
They have toxic chemicals
A combination of the above defenses
Dry and wet
Winter and summer
Winter and fall
Spring and summer
Tundra
Desert
Temperate forest
Grassland
Growing quickly
Having deep roots
Developing fire-resistant cover
All of the above
They avoid each other as much as possible
They all migrate in different directions
They eat different foods
Their territories don't overlap