Which of these is the largest?
a. star
b. nebula
c. galaxy
d. sun

World class speed skaters can skate a 3,000-m course in about 4 minutes. what is their average speed for this course? a. 12.5 m/sb. 1.33 m/sc. 1.25 m/sd. 13.3 m/s

Afrequency generator sends a 550 hz sound wave through both water and ice. what is the difference in wavelength between the wave produced in ice and the wave produced in water?

What was the first instrument to ever record an earthquake?