L4：
讲座
1. What is the lecture mainly about
A method that is used to determine an animal’s diet
How scientists determine where migratory birds stop to feed
The different forms of carbon that can be found in animals
How migratory birds find different types of food at stopover sites
2. How did researchers find out what a bird ate at different times during migration
By taking samples of the bird’s breath at different places on the migration route
By having the bird wear a device that records what it eats during its journey
By taking samples of the bird’s breath and several of its body tissues
By observing bird feeders along the migration route
3. According to the professor, what are two possible reasons that white-throated sparrows eat corn on Block Island
The birds normally eat corn throughout the year.
The berries that they usually eat are not available.
The corn provides good nutrition for long flights.
The birds can easily locate corn growing on farms.
4. According to the professor, what might be the practical application of studying the diet of white-throated sparrows
It will help Block Island farmers protect their crops.
New methods of determining changes in diet can be developed.
Feeding white-throated sparrows will prevent them from migrating in the winter.
Migrating white-throated sparrows will be provided with the most appropriate diet.
5. What do biologists hope to find out by using breath collectors on bears
Whether the diet of bears changes when they are nursing
How the amount of meat in the diet of bears affects their health
How the bears’ ability to nurse their young varies
Whether the diet of bears affects the carbon signature in their blood
6. Why does the professor say this:
To indicate that she would enjoy doing this type of research with bears
To indicate that this type of research is easier to do with birds than with bears
To encourage students to volunteer for research projects
D. To encourage students to express their opinions
