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