Answer:
Tundra :a vast, flat, treeless Arctic region of Europe, Asia, and North America in which the subsoil is permanently frozen.
Temperate grasslands are characterized as having grasses as the dominant vegetation.
Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as lowland equatorial evergreen rainforest.