L3：
讲座
1. What’s the main purpose of the lecture?
To explore a possible similarity between manatees and fish
To explore recent research on animal hair types and her functions
To show how marine mammals have adapted to various ocean environments
To present a theory about the various functions of animals’ lateral lines
2. What are three factors mentioned by the professor that affect manatees’ ability to navigate?（多选题）
Their large body size
Their poor vision
Their inability to echolocate
The rate of water flow in their habitat
The level of visibility in their habitat
3. How do tactile hairs differ from other hairs?
A. They are softer to the touch.
They stimulate more nerves when they move.
They can sense changes in temperature.
They grow in straight-line patterns.
4. What does the professor imply about manatees’ tactile hairs?
A. They might serve the same function as a lateral line.
BThey probably evolve to help manatees hear better.
CThey are useful only during a limited period of a manatee’s life.
DThey are located only on the manatees’ faces.
5. What can be inferred about the recent research into manatees’ hair follicle sinuses?
The research explains why manatees can survive on land as well as under water
The research returned contradictory findings.
The research has led scientists to search for hair follicle sinuses on other marine mammals.
The research confirmed what one scientist had already suspected
6. According to the professor, what is a question that the researchers are investigating?
How manatees’ navigational abilities compare to those of whales and dolphins
How changes in water visibility can affect manatees’ ability to navigate
Whether manatees can detect motionless objects in water
D. Whether manatees can remember specific routes to food source
