(C)we use sound and sight, they depend primarily on pheromones", chemicals secreted" by
individuals and smelled or tasted by nestmates. ( D) the brain of an ant weighs less than one-
millionth as (E ) as a human brain, it is not surprising that a given species produces just ten to
twenty signals. Unlike human language, these messages are entirely instinctual.
These marvelous little creatures have been on Earth for more than 140 million years. The most