Edward Wilson is America's, if not the world's, leading naturalist. In The Future of Life, he takes us on a tour of the world's natural resources. How are they used? What has been lost? What remains and is it able to continue with the present speed of use? Wilson also points out the need to understand fully the biodiversity(生物多样性)of our earth.
Wilson begins with an open letter to the pioneer in environment protection, Henry David Thoreau. He compares today's Walden Pond with that of Thoreau's day. Wilson will use such comparisons for the rest of the book. The problem is clear: man has done great damage to his home over the years. Can the earth, with human help, be made to return to biodiversity levels that will be able to support us in the future?
Biodiversity, Wilson argues, is the key to settling many problems the earth faces today. Even our agricultural crops can gain advantages from it. A mere hundred species(物种) are the basis of our food supply, of which but twenty carry the load. Wilson suggests changing this situation by looking into ten thousand species that could be made use of, which will be a way to reduce the clearing of the natural homes of plants and animals to enlarge farming areas.
At the end of the book, Wilson discusses the importance of human values in considering the environment. If you are to continue to live on the earth, you may as well read and act on the ideas in this book.
We learn from the text that Wilson cares most about       .

A．the environment for plants

B．the biodiversity of our earth

C．the waste of natural resources

D．the importance of human values

How many species are most important to our present food supply?

A．Twenty

B．Eighty

C．One hundred

D．Ten thousand

Wilson suggests that one way to keep biodiversity is to        .

A．learn how to farm scientifically

B．builds homes for some dying species

C．makes it clear what to eat

D．use more species for food

We can infer that the text is         

A．description of natural resources

B．a research report

C．a book review

D．an introduction to a scientist