The primary purpose of the passage is to A. settle the question of whether orb webs evolved once or more than once B. describe scientific speculation concerning an issue related to the evolution of orb webs C. analyze the differences between the characteristic features of spiders in the Araneidae and Uloboridae families D. question the methods used by earlier investigators of the habits of spiders E. demonstrate that Araneidae spiders are not related to Uloboridae spiders