Identify what are two unique characteristics shared by all birds?

Tropical rain forests support more species per unit area than any other terrestrial ecosystem. what is one way rain forests are important to the health of the biosphere?

The structure that houses the cells genetic information.

Ascientist publishes a paper that states the changes in the levels of gases in the atmosphere of a moon of saturn indicate that there may be terrestrial life on the moon. which statement correctly answers whether the question of alien life on this moon is scientific?