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