The "ufc" data we examined in last chapter's exercises can be loaded from ufc.csv (in the "data" directory of EssentialR). This contains data on forest trees, including Species, diameter (in cm, measured 4.5 feet above ground and known as "diameter at breast height" or Dbh), and height (in decimeters). Make a single barplot showing both variables (Dbh and Height) for each Species and include errorbars (either SE of the mean or 95% CI) and a legend. Hint: In Ch 15 we saw how to add a secondary y-axis - with a barplot you need to specify the x-axis limits and change the width= and space= arguments to make the bars narrower and to get the bars to plot side-by-side