Marco is making blueberry muffins. The ratio between flour and blueberries for the recipe being used is shown in the table below. How many cups of blueberries will Marco need if he has 2 cups of flour to use?
According to the table, the ratio of flour to blueberries is 2:1. This means for every 2 cups of flour, there is 1 cup of blueberries.
Therefore, if Marco has 2 cups of flour to use, he will need 2/2 = <<2/2=1>>1 cup of blueberries. Answer: \boxed{1}.