★ Biology Quiz
Hydrogen, chlorine, and sodium are examples of ___.
A. compounds
B. elements
C. molecules
D. isotopes
Select your answer:
Topics:
Neurology Heart Structure and Double Circulation Multicellular Organisms Psychology Vocabulary Bacteria & Viruses Fainting and Nosebleed Central Nervous System Musculoskeletal Protein Synthesis Enzymes Cellular Transport and Metabolism The Human Eye Endocrine System Carbohydrates Respiratory Diseases The Digestive SystemOther quiz:
Respiratory System › ViewThe walls of the alveoli and capillaries are permeable. What does this mean?
A. Substances can pass through them.
B. They are made of muscle.
C. They are located throughout the body.
D. They are made of bone.
The Brain › View
What system contains the brain and spinal cord?
A. central nervous system
B. digestive system
C. respiratory system
D. peripheral nervous system