2026年1月托福机经套卷(第9套)Read an Academic Passage5 道题

Bird Migration

阅读材料

Bird Migration Every year, millions of birds travel huge distances to wintering grounds, and then back to breeding grounds when warmer weather returns there. Bird migration evolved in response to climatic changes. During the Ice Age, when average temperatures were frigid, migrating birds had a survival advantage, and the behavior became widespread. Migration is also linked to resource availability. Arctic terns, which undertake the longest migrations of any animal by flying from their summer breeding grounds in Earth's north polar (Arctic) regions to their wintering grounds in Earth's south polar regions, feed primarily on small fish and other small marine animals. This prey is most abundant when increased sunlight results in the increased availability of algae, the microscopic marine plantlike organisms that are food for the tiny marine animals known as zooplankton, which are in turn consumed by terns' prey. Not all birds migrate. Rock ptarmigans also live in Arctic and sub-Arctic regions. Instead of flying to warmer climes in winter, they shelter in snow burrows and reduce activity to conserve energy. They feed on plants like birch and willow trees, which are available in their habitat year-round. The divergence between migratory and sedentary species represents different adaptations to environmental pressures.

Question 1查看单题

The passage implies that bird migration began when

Awintering grounds were closer to breeding grounds than they are now

Bareas suitable for breeding were smaller than they are now

Cthere were many more birds than there are now

Dclimates were generally much colder than they are now

查看答案

正确答案：D

下一题 ↓

Question 2查看单题

What is the passage explaining when it mentions that "increased sunlight results in the increased availability of algae"?

AWhy terns' migrations result in increased food availability for them