Table: race_results_68
Columns: year
entrant
chassis
engine
points

Question: In 1972, how many points did the entrant with the March 721G Chassis have?
SQL: SELECT "points" FROM race_results_68 WHERE "year" > 1972 AND "chassis" = 'march 721g'

Question: In 1971, how many total points did the entrant stp march have?
SQL: SELECT COUNT("points") FROM race_results_68 WHERE "entrant" = 'stp march' AND "year" > 1971

Question: Which Chassis was featured in the year 1971?
SQL: SELECT "chassis" FROM race_results_68 WHERE "year" = 1971

Question: Which Chassis did the Entrant clarke-mordaunt-guthrie-durlacher carry?
SQL: SELECT "chassis" FROM race_results_68 WHERE "entrant" = 'clarke-mordaunt-guthrie-durlacher'