Which pair contains only physical quantities that vary with temperature and so could be used in making a thermometer?

A activity of a radioactive source, volume of a gas
B mass of a liquid, volume of a liquid
C activity of a radioactive source, mass of a solid
D volume of a gas, volume of a liquid

Aplane travels 1000 miles in 5 hours .what is the planes average speed?

Using a pedometer, you walk 3000 steps in 20 minutes, so your speed is 150 steps/min. each of your steps is 0.7 m long. what is your speed? 150 steps/min=/s=/h

What changes occur in the brain during the teenage years? 25 points, someone me out!a.) thinking becomes slower as the brain grows larger. b.) connections between neurons become stronger and faster. c.) unused neurons fuse together to form larger, better functioning neurons. d.) more neurons are developed.