What were the first organisms to appear on Earth?

What can contribute to potential global warming by?

why are current radiation and chemotherapy treatments not always effective in preventing the reoccurrence of cancer?

How does the rock cycle transform rocks from one type to another?

Jacob has just gotten an interview for a job he really wants. With his excitement, his heartbeat increases, his blood pressure rises, and he begins to perspire. Which nervous system is responsible for these physiological changes?

Hybrid car batteries contain the rare elements neodymium and lanthanum these substances are

Which functional group allows the sugar glucose to dissolve in blood? a. Carboxyl b. Hydroxyl c. Phosphate

A protein is in its native conformation when a. it is thermodynamically least stable b. it has the highest gibbs free energy c. it is in any of its functional, folded states d. it is unfolded e. none of the above

If a single female immigrant brings a trait to a small, sparsely populated island and within many generations it is present in 50% of the population, it would be an example of

3. How big is the Clark Refractor in Arizona?

Radioactive uranium-235 has a half-life of 704 million years. If it was incorporated into dinosaur bones, could it be used to date the dinosaur fossils?