The flowers are used in reproduction. They evolved during the Cretaceous period . An apomorphy is a new genetic characteristic common to a clade . Feathers are an apomorphy for birds. Many plants are aquatic, including seaweeds .
Many animals are arboreal, including the sugar glider.
An arid area is dry and hot, with little rainfall and few plants. An asteroid is a large rock or small planet orbiting the Sun. Most asteroids lie in a belt between Mars and Jupiter . An asteroid impact with the Earth may have caused the K-T mass extinction. The atmosphere is the mixture of gases that surrounds the Earth.