Ⅳ. Cloze Echolocating bats 21 sounds in patterns—characteristic of each species—that contain both frequency-modulated (FM) and constant-frequency (CF) signals. The broadband FM signals and the narrowband CF signals travel out to a target, reflect from it and return to the hunting bat. In this process of 22 and reflection, the sounds are changed and the changes in the echoes enable the bat to perceive features of the target. The FM signals report information about target characteristics that modify the timing and the fine frequency structure, or spectrum, of echoes—for example, the target’s size, shape, texture, surface, structure, and direction in space. Because of their narrow bandwidth, CF signals portray only the target’s presence and, 23 some bat species, its motion 24 the bat’s. 25 changes in the CF echo’s frequency, bats of some species correct in flight for the direction and velocity of their moving prey.