THIS IS A SCIENCE QUESTION Which choice describes how temperature differences affect air?

A. Hot air rises, and cold air sinks.

B. Hot air sinks, and cold air rises.

C. Hot air is steady, and cold air moves fast.

D. Hot air moves fast, and cold air rises.

Stage in which a star’s outer layers have started to cool and grow outward?

Which is an example of the practical pursuit of alchemy? a. forming perfect substances. b. transforming base metals. c. developing metalworking techniques. d. linking spiritual characteristics with material substances.

Before it was launched, a helium-filled balloon had a pressure of 201 kpa at a temperature of 27°c. at an altitude of 15,000 m, the pressure had decreased to 2.5 kpa and the temperature had dropped to -14 °c. the volume of the balloon increased to 59.3 m3. what is the original volume of the balloon? 13 m3 0.85 m3 0.077 m3 1.17 m3