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