Why could tropical rain forests be called the "medicine chest of the Earth?

The similarities of organisms in which two areas numbered above provide the best evidence for common ancestry between organisms in both locations?

How does secondary succession differ from primary succession?

What's wrong with this ecological pyramid? (multiple choice)1. secondary consumers should be at the bottom of the pyramid2. the sun has an arrow leading to decomposers 3. primary consumers should come after the sun4. energy retained should increase from the bottom to the top5. the sun should be at the bottom of the pyramid