更多"Scientists gather information about"的相关试题:
[填空题]Scientists gather information about climate systems and use this information to ______.
[单项选择]Climate change has brought about such problems as bleaching-induced (47)______ of corals.
Bleaching occurs when corals are stressed by high temperature or other (48)______ changes, and lose their symbiotic algal cells. When they lose these cells, which provide the corals with essential (49)______ and give them their color, they can die. Reefs are important for livelihoods, and fisheries and tourism, and are the main (50)______ along the eastern African coast as well as (51)______ many of the islands of the Western Indian Ocean.
In college during the 70s, I joined an expedition to the Malindi Marine Park -- one of the first MPAs (marine protected areas) to be established in Africa-where we (52)______ in a well-protected reef. But over the years, that reef has been completely devastated by the bleaching. It was truly (53)______ to see such a vibrant and healthy reef reduced almost to the status of an unprotected one.
Recently, coral reefs have received a great deal of atte
[单项选择]A period of climate change about 130,000 years ago would have made water travel easier by lowering sea levels and creating navigable lakes and rivers in the Arabian Peninsula, the study says. Such a shift would have offered early modern humans--which arose in Africa about 200,000 years ago—a new route through the formerly scorching northern deserts into the Middle East. The new paper was spurred by the discovery of several 120,000-year-old tools at a desert archaeological site in the United Arab Emirates. The presence of the tools—whose design is uniquely African, experts say—so early in the region suggests early humans marched out of Africa into the Arabian Peninsula directly from the Horn of Africa, roughly presentday Somalia. Previously, scientists had thought humans first left via the Nile Valley or the Far East.
"Up fill now we thought of cultural developments leading to the opportunity of people to move out of Africa," said study co-author Hans-Peter Uerpmann, a retired arch
A. aboriginal.
B. primitive.
C. luxuriant.
D. baking-hot.
[单项选择]
What can we learn about the climate
A. It’s cold and gloomy.
B. It’s changeable.
C. It is constant.
[单项选择]An analyst does research about duration and gathers the following information about two option-free bonds in a portfolio:
| Bond | Par value | Market value | Duration |
| 1 | $120000 | $110000 | 5 |
| 2 | $80000 | $90000 | 4 |
The duration of the portfolio is closest to:（）
A. 4.33
B. 4.40
C. 4.55
