16.There are a large number of ants worldwide.Each individual (個人的) ant hardly weighs anything,but put together they weigh the same as all of mankind.They also live nearly everywhere,except on cold mountain tops and around the poles.For animals their size,ants have been surprisingly successful,largely because of their wonderful social behavior.
In colonies (群體) that are changing in size from a few hundred to tens of millions,they organize their lives with a clear division(分工) of labor.Even amazing is how they achieve this organization.Where we use sound and sight to communicate,ants depend on pheromones (外激素),chemicals sent out by individuals and smelled or tasted by fellow members of their colony.When an ant finds food,it produces a pheromones that will lead others straight to where the food is.When an individual ant comes under attack or is dying,it sends out an alarm pheromone to warn the colony of danger.
In fact,when it comes to the art of war,ants have no equal.They are completely fearless and will take on an animal much larger than themselves,attacking in large groups and achieve their goal.Such is their devotion to the common good of the colony that not only soldier ants but also worker ants will lose their lives to help win an enemy.
Behaving in this selfless and devoted way,these little animals have survived on Earth for more than 140million years,longer than dinosaurs.Because they think as one,they have a united intelligence greater than you would expect from its individual parts.
12.We can learn from the passage that ants areA.
A.not found around the poles
B.too many to achieve any organization
C.not willing to share food
D.more successful than all other animals
13.Ants can use pheromones forD.
A.escape
B.warning enemies
C.a(chǎn)rranging labor
D.communication
14.What does the underlined expression"take on"in Paragraph 3mean?C
A.Accept
B.Play with
C.Fight against
D.Employ
15.Which of the following accounts for the survival of ants?A
A.Their behavior
B.Their size
C.Their number
D.Their weight.