SECTION 3 Directions: Each passage in this group is followed by questions based on its content. After reading a passage, choose the best answer to each question. Answer all questions following a passage on the basis of what is stated or implied in the passage. Researchers have noted that ants arrange their dead using the same principles thought to produce the markings on animal skin and on tropical sea shells, a first clear example of so-called Turing patterns in higher organisms. Line Turing argued that activation occurs through a feedback process that amplifies (5) small variations in the concentration of one of the ingredients, while inhibition causes a concentration of activity to suppress the appearance of similar concentrations nearby. Ant graveyards are an example of a self-amplifying activation process: ants are more likely to drop a corpse on a pile than elsewhere, and because collecting bodies and adding them to a pile sweeps the (10) surrounding space clear, new cemeteries are inhibited from appearing in the vicinity of existing ones. While activator-inhibitor mechanisms have previously been proposed to explain how predators and prey distribute themselves across an ecosystem, it is the first time such a system has conclusively proven that Turing's process operates at the level of colonies and ecosystems. The main idea of the passage is that