What might be a symptom of a person whose vein valves are not functioning properly and are causing fluid to flow away from the heart?

Diagram of the evolution of land plants?

Antoine manages a number of apartment buildings that use natural gas for heating, cooking, and laundry. the scatter plot shows the correlation between the outside air temperature and antoine's natural gas bill. which type of correlation does the plot illustrate?

The main ingredient of magma is a pahoehoe. b silca c dissolved gases d obsidian