(2025·扬州)Many marine species(海洋物种) depend on specific routes to migrate(迁徙). The routes offer these seafaring travellers the right conditions, at the right time of year, to guide them through the oceans. We humans try to discover the routes and have drawn our own lines, but they are not clear to us because of unexpected changes in nature.
To find out the routes that migratory marine species regularly take, a research team of scientists in Australia and the USA have now created an interactive map that shows the paths connecting ocean habitats(栖息地).
The new map, named the Migratory Connectivity in the Ocean(MiCO), collects data and makes it easier for scientists to see where migratory marine species may be falling into the paths. The database(数据库) includes information on 109 species, based on around 30 years of data, and shows where they are going to and from—including which species cross into whose national waters.
"MiCO connects almost 2,000 important habitats and shows the importance of cross-boundary teamwork," says the research team. They find that all of the species recorded in MiCO have less protection at some point in their life history because of different situations in different countries. That means no country is able to fully protect migratory species if there is no help from others. "For example, green turtles nest in Costa Rica and migrate north through Nicaragua and out to islands in the Caribbean," the team says. "Although largely protected in Costa Rica, it is allowed to fish for turtles in Nicaragua and huge numbers are lost off the coast there every year."
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()42. How does the writer lead in the topic?

A.By offering advice.
B.By presenting study results.
C.By expressing opinions.
D.By giving background information.
答案：D