Most of the world's population lives in: north americaonly a few countriesdeveloped countrieseurope

What protects the lining of the stomach from acidic gastric juices?

How does the molecular clock work? a. it analyzes the brain functionality of two different species.b. it examines and compares the physical characteristics of two different species.c. it illustrates relationships between two different species.d. it compares the number of mutations that exist in the dna of two different species.

What are some possible short and long term medical concerns for crew members on longer space exploration trips