Which elements are in the substance that makes up 60% of the human body.

A. hydrogen and oxygen

B. phosphorus and nitrogen

C. calcium and oxygen

D. carbon and phosphorus

What makes heart muscles contract, thereby regulating heart rate?

In what way does the transform boundary differ from the other three boundary types? Transform boundaries are always found on the ocean floor. Transform boundaries can result in volcanic activity.

Lipids are organic macromolecules that serve a variety of purposes. What is the most important role of lipids?

Name five elements other than carbon that are found in organic compounds

Which of the following it biodegradable? a. A nylon jacket b. A plastic cup c. A television set d. A wool sweater

How are all living thing made of cells

Which is am example of an internal stimulus? A) an increase in the amount of water available to a plant B) an artificial light attracts insects C) a decrease in oxygen levels in the blood during exercise D) a sudden change of air temperature

How dose one determine when an ecosystem is in balance

How does respiratory system relate to respiration making ATP?

What is the largest group of reptiles that ever lived?