B
Seagrass, an underwater plant that grows on the ocean floor, is very important for sea life. It also helps prevent global warming by storing carbon, a harmful gas. However, scientists don’t know exactly how much seagrass is at the bottom of the ocean. With the help of tiger sharks, a team of researchers has discovered the world’s largest seagrass meadow (grassland) on the seafloor near the Bahamas.
Seagrass meadows are home to many different kinds of fish, shellfish, and so on. Large sea animals, such as sharks, also spend a lot of time there looking for food. Seagrass can grow in very deep and dark waters, making it difficult to find. But sharks can dive deep into the water and get to the areas people cannot reach.
After noticing tiger sharks swimming through seagrass off the Bahamas, an American scientist worked with a seagrass expert(专家), trying to map the locations of the plants. The researchers fitted seven tiger sharks with cameras. Since tiger sharks swim in groups, they placed satellite tracking tags(卫星跟踪器) on eight other sharks to find out exactly where the animals swam. They collected hours of videos of the tiger sharks swimming through seagrass.
The researchers found more seagrass growing near the Bahamas than they expected—in fact, they believe that there is more seagrass there than anywhere else on earth. The new finding increased the total amount of seagrass known to exist by 41%. However, more research is needed to discover the true size of the seagrass meadow.
Scientists often depend on findings from divers and boats to study about the underwater world, but this team found that working with animals improved their understanding. They are now placing cameras on sea turtles to study seagrass in the Red Sea. Hopefully, more mysteries about seagrass will be solved.
(
) 4. Why is seagrass difficult to find underwater?
A. Seagrass is too small to be seen.
B. It grows in very deep dark areas.
C. It’s difficult to reach the bottom of the sea.
D. Tiger sharks almost eat it all up.
(
) 5. What is paragraph 3 mainly about?
A. The reason for the research.
B. The method to do the research.
C. The discovery of the research.
D. The scientists of the research.
(
) 6. How will scientists work out mysteries about seagrass?
A. By hiring more divers and boats.
B. By using better cameras.
C. By having discussions with experts.
D. By working with animals.
(
) 7. The passage is written to
.
A. show a special project on global warming
B. express the features of some big sea animals
C. share a new way of doing undersea research
D. tell the importance of seagrass in big oceans
