Answer:
The alveolar walls and capillary walls share a membrane. That's how close they're getting. This allows oxygen and carbon dioxide to readily pass from the respiratory system to the circulation. Oxygen molecules bind to red blood cells as they return to the heart.
Valine, Leucine & Isoleucine
Alanine
Arginine
Glutamine
Lysine
Aspartic acid
Glutamic Acid
Proline
Cysteine
Threonine
Methionine
Histidine
Phenylalanine
Tyrosine
Tryptophan
Asparagine
Glycine
Serine
Answer:
because the atomic number tells you how many protons and neutrons there are
Explanation: