reverse crunches and leg lifts. a simple google or youtube search of "lower ab exercise" will yield you About 1,640,000 results in (0.09 seconds). As somebody whose goal was to get fit this summer, im telling you that theses exercises are the hardest because we dont use the lower abs in everyday life. so it will seem really tough at first but dont give up.
Can't lose weight in one area, your heart rate must be between 140 and 160 to burn fat, I suggest cardiovascular workouts.
well you could try crunchs and hollows