試題詳解

25. The author mentions the trail pheromone of the leafcutter ant in line 11 to point out
(A) how little pheromone is needed to mark a trail
(B) the different types of pheromones ants can produce
(C) a type of ant that is common in many parts of the world
(D) that certain ants can produce up to one milligram of pheromone