The mass is made up of protons and neutrons, the valence electrons only determine stability, not mass
The folds in the stomach lining are called rugae. On these rugae, you will find a thin line of mucous which helps protect the stomach lining. The innermost layer is called Simple Columnar Epithelium.
Answer:
The Circulatory System
Explanation:
When blood is rich in carbon dioxide it leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs. (All of which have to do with the circulatory system)
D- the frequency of the recessive alle increases over time