Astudent holds a tuning fork oscillating at 259 hz. he walks toward a wall at a constant speed of 1.31 m/s. (a) what beat frequency does he observe between the tuning fork and its echo? hz (b) how fast must he walk away from the wall to observe a beat frequency of 4.90 hz? m/s

Which of the following statements about protists are true? a.they are typically found in moist environments. b.they are all unicellular. c.they have a nucleus. d.they are all multicellular.

Internal feedback works to maintain homeostasis when your a. heart rate decreases as your white blood cells increase b. breathing rate decreases as your red blood cells decrease c. heart rate increases as your liver is cleaning blood d. breathing rate increases as your heart rate increases

Who discovered tuberculosis bacteria?