Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

A common cause of iron deficiency anemia in adulthood is

Which organism is probably responsible for keeping the food web and the pyramids in their respective shapes? The Earth is an open system for energy. Explain what that means using evidence from pyramids.

How are frogs adapted for terrestrial life? If frogs have lungs, why do they also breathe through the skin?

List 2 stars that can be seen from earth and describe their brightness, distance and color

Select the correct answer. Which boundary involves two high-density plates that form deep, narrow trenches along the boundary? A. oceanic-continental convergent boundary B. oceanic-oceanic convergent boundary C. divergent boundary D.

An area of land that is covered with a shallow layer of water during some or all of the year is called

What is the role of the atp in the cell

What Are Genes? A. the observable characteristic B. the expressed trait C. the basic unit on inheritance D. the measurable factor

Which best describes oogenesis and spermatogenesis?

What is one thing that all types of asexual reproduction have in common?