A group of scientists set out to estimate (估计) the number of ants on Earth. According to their research, there are about 2. 5 million ants for every human on the planet. Then the scientists held 489 studies of ant populations.

The studies covered all kinds of habitats including cities, deserts and forests. The researchers find that most ants live in tropical (热带的) areas and that they are more commonly found in forests and dry areas than in human-made habitats. In addition, the scientists find that the population of ants is more than the number of all the world’s wild birds and animals together.

The researchers say this number is a low estimate. This is because they did not have much information on how many ants live underground. Besides, there were not many trusted studies about how many ants live in certain parts of the world, like Africa.

Ants play very important roles in the environment. They help to spread seeds, help water reach plant roots, and are a kind of food for many living things. Patrick, who did this new estimate, said, “I am sure the whole nature would simply break down without ants.”

For checking their populations, it is useful to estimate how many ants there are. Then the scientists can see if they are becoming less because of harmful changes in the environment worldwide, the number of insects, a group that includes ants, is becoming less. However, it is not clear if the number of ants is becoming less as well.

【小题1】According to the passage, where are ants commonly found?

A．In wet areas and forests.	B．In tropical areas.
C．In human-made habitats.	D．In the water.

【小题2】The underlined word “habitats” in paragraph 2 means _________.

A．natural homes of ants	B．living areas of people
C．good conditions for ants	D．working places for people

【小题3】What causes the number of ants to be a low estimate?
①There aren’t many ants in forests.
② Scientists don’t know how many ants in certain areas.
③The studies are mainly held in the cities.
④ The studies aren’t sure about ants underground.

A．①③

B．①④

C．②③

D．②④

【小题4】What’s the genre (体裁) of the passage?

A．Information writing that gives information about something.

B．Narrative writing that allows the writer to tell a story.

C．Creative writing that uses the imagination to express meaning.

D．Poetry that is a collection of poems.

【小题5】What would be the best title for the passage?

A．Finding the Change of Arts.	B．Studying the Life of Ants
C．Rebuilding the Home of Ants	D．Researching the Number of Ants