Insect-eating bats rely heavily on echolocation, a method of sensory perception by which certain animals orient themselves to their surroundings, detect obstacles, communicate with others, and find food. While using echolocation, these bats emit a series of short, high-frequency sounds from their mouths or nostrils that bounce off objects and surfaces and then return to the animals’ ears. Since high-frequency waves do not diffract, or bend, extensively, these ultrasonic vibrations provide bats with accurate maps of their surroundings. The biosonar of some bats is so advanced that it allows them to fly in complete darkness, snatch moving insects out of the air, or hover just above water level to drink.
For years, scientists have been aware that bats emit slightly different frequencies in differing situations. Recent research has provided insight into how certain physical features help bats use this variability to differentiate among objects in their environments. Many species of bats have elaborate, intricately shaped flaps, or noseleaves, around their nostrils that are adorned with grooves and spikes. Three-dimensional computer simulations of these noseleaves revealed that furrows along the top of the noseleaves act as cavities that resonate strongly with certain frequencies of sound. As a result, the grooves cause different frequencies of sound to discharge in different directions. Lower frequency sounds are spread more vertically, while higher frequency sounds emit more horizontally. The complexity the noseleaves add to the bats’ ultrasound perception could help the bats perform difficult tasks, such as locating prey while avoiding obstacles.
1. Which of the following best describes the relation of the second paragraph to the first paragraph?
(A) The second paragraph discounts the complexity of a process that is revealed in the first paragraph.
(B) The second paragraph clarifies a debate over a biological system that is discussed in the first paragraph.
(C) The second paragraph illuminates the intricacies of a method that is introduced in the first paragraph.
(D) The second paragraph explains the results of a hypothesis that is expressed in the first paragraph.
(E) The second paragraph describes the function of a physical feature that is mentioned in the first paragraph.
2. Which of the following, if true, would most weaken the conclusion concerning the purpose of bats’ noseleaves?
(A) The range of frequencies that bats hear is much smaller than the range of frequencies that bats emit.
(B) Many bats emit echolocation sounds through their mouths rather than through their noses.
(C) Dolphins rely on echolocation, and they do not have noseleaves.
(D) When their food sources are stationary, some bats rely on eyesight and smell rather than echolocation.
(E) The sound waves emitted during echolocation are limited to a range of fewer than one hundred feet.
3. Which of the following can properly be inferred from the passage?
(A) The sound waves a bat emits during echolocation only travel parallel or perpendicular to the bat's motion.
(B) The spikes found on bats’ noseleaves are rarely utilized during echolocation.
(C) Many insect-eating bats do not possess a well-developed sense of sight.
(D) Low-frequency sound waves diffract less extensively than high-frequency sound waves.
(E) During echolocation, bats do not rely on low-frequency sound waves.
Please provide explanations/approaches for question 2 and 3 given above. Thanks.