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