What are the four types of galaxies?

What is associated with mid-ocean ridges?

Reading graphs: unemployment us unemployment rate (1961-2011) identify the trends in the graph and then use the drop- down menu to complete each statement from 1961 to 1965 unemployment was in the mid-2000s through 2011. unemployment was percentage unemployed 1961 1971 1981 1991 2001 2011 year

These factors threaten north americas ecosystems