What of the following is correct with respect to the 2 H and 18 O isotopes of water: a. Lighter isotopes evaporate later, heavy isotopes condense later b. Lighter isotopes evaporate later, heavy isotopes condense earlier c. Lighter isotopes evaporate earlier, heavy isotopes condense earlier d. Lighter isotopes evaporate earlier, heavy isotopes condense later QUESTION 7 What does the rain ratio refer to in ocean material flux studies? a. Ratio of wet to dry deposition in the ocean b. Organic carbon to CaCO 3 carbon in sinking materials c. Really Awesome is Nature d. Organic carbon to CO 2 in rain falling on the ocean.