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