What do all organic compounds have in common ?

Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins

"your temperature analysis reveals a pattern with coldest temperatures located to the portion of the map."

Wich is not standing in the way of astronomers getting a good view of different star