What is the process by which sand dunes occur? a. wind carries up the windward side of the dune and drops it over on to the leeward side. b. wind carries up the leeward side of the dune and drops it over on the the windward side. c. ocean waves and gravity move the dunes. d. sand dunes don't move.

Consider the following reaction at equilibrium: c(s)+h2o(g)⇌co(g)+h2(g) predict whether the reaction will shift left, shift right, or remain unchanged upon each of the following disturbances. a) c is added to the reaction mixture. b) h2ois condensed and removed from the reaction mixture c) co is added to the reaction mixture d) h2 is removed from the reaction mixture.