1. Frank counts 56 maple trees living on a 20-acre tract of land. He calculate the (population density I population distribution / growth rate / reproductive rate) of the maple trees on the land. He observes that most of the maple trees grow closely together in groups of 6 to 8 trees, which describes the (population density / population distribution / growth rate / reproductive rate). The (population density population distribution/ growth rate i reproductive rate) of the maple trees shows the percentages of trees of different ages.​