题目内容：

    Anyone who commutes (通勤) by car knows that traffic jams are an unavoidable part of life. But humans are not alone in facing potential backups.

Ants also commute—between their nest and sources of food. The survival of their colonies depends on doing this efficiently.

When humans commute, there’s a point at which cars become dense (稠密) enough to slow down the flow of traffic, causing jam. Motsch, a mathematician in Arizona State University, and his colleagues wanted to know if ants on the move could also get stuck. So they regulated traffic density by constructing bridges of various widths between a colony of Argentine ants and a source of food. Then they waited and watched. “The goal was to try to find out at what point they are going to have a traffic jam.” said Sebastien Motsch.

But it appears that that never happened. They always managed to avoid traffic jam. The flow of ants did increase at the beginning as ants started to fill the bridge and then levelled off at high densities. But it never slowed down or stopped, even when the bridge was nearly filled with ants.

The researchers then took a closer look at how the behaviour of individual ants impacted traffic as a whole. And they found that when ants sense overcrowding, they adjust their speeds and avoid entering high-density areas, which prevents jams. These behaviours may be promoted by pheromones, chemicals that tell other ants where a trail is. The ants also manage to avoid colliding (碰撞) with each other at high densities, which could really slow them down. The study is in the journal eLife.

Can ants help us solve our own traffic problems? Not likely, says Motsch. That’s because when it comes to getting from point A to point B as fast as possible, human drivers put their own goals first. Individual ants have to be more cooperative in order to feed the colony. But the research could be useful in improving traffic flow for self-driving cars, which can be designed to be less like selfish humans—and more like ants.

1.What does the underlined word “this” in para.2 refer to?

A.Surviving. B.Commuting.

C.Finding food. D.Avoiding jams.

2.How did the researchers control the traffic density of the commuting ants?

A.By finding out the dense points. B.Through closer observation.

C.By controlling the widths of their path. D.By regulating their numbers.

3.According to the research, ants can avoid traffic jams mainly because ________.

A.they follow a special route.

B.they level off at high densities.

C.they never stop or slow down on the way.

D.they depend on their natural chemicals to adjust their speeds.

4.What is the best title of the passage?

A.Traffic jams. B.Unavoidable? Not for ants!

C.Survival of an ant colony. D.Difference between human and ants.