3. Mesa: a high plateau with steep sides. Mensa: table
4. Equinox: the time when the sun crosses the equator making day and night of equal length in all parts of the earth. Nocturnal: active during the night. Nox: night
11. Assume: to take on the appearance or role of. Consume: to use up. Presume: to take for granted; suppose. Resume: to take or occupy; to continue. Sumo: to eat or take.
12. Annul: to do away with. Null: of no value. Nullify: to cancel out. Nullus: not any.