The density function of heights of trees in a city park is shown in the figure. To use this interactive graph, click and drag the red dot. (Be patient -- the interactive applet may take a minute to load.)

1. How many different species of trees would you estimate are planted in this city park? ? 0 1 2 3 5 6 7 8 9 10
   
   
2. In this city park, 20% of the trees have height meters or less.
   
   
3. In this city park, the fraction of trees of height 4 meters or less is .