(Q).
Q: What causes cumulus clouds to grow upward? Choices: - moisture currents - gas currents - mantle currents - convection currents A:
(A).
convection currents

(Q).
Q: What do you call mixtures of ash and water that travel down river valleys? Choices: - debris - pollutants - mud slides - lahars A:
(A).
lahars

(Q).
Q: Bread has little holes in it from carbon dioxide produced by what? Choices: - sugar - water - bacteria - yeast A:
(A).
yeast