Audible beats are formed bu the interference of two waves
a. of slightly different frequencies
b. of greatly different frequencies
c. with equal frequencies, but traveling in opposite directions
d. from the same vibrating source.

After a car's engine has been running for a while, if you stand near the car's engine you can often feel heat coming from the engine as a result of a. radiation b. convection c. conduction

Which lists the main components of darwin’s theory of evolution? a. random mutations drive evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms do not change. b. natural selection drives evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms change over time. c. natural selection drives evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms change over time. d. random mutations drive evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms do not change.

Assume similar data for the motion of the blood in your aorta. estimate how many beats of the heart it will take the blood to get from your heart to your brain. (assume that the distance from your heart to your brain is 30 cm)