What exercises work out the lower pectorals?

sit ups, pull ups, run, walk, jog, and etc.

Squats, deadlifts, and leg presses and their variations will do that for you.

There are many exercises that you can use. For instance push-ups, bench press with barbell or dumbbells (flat bench, incline and decline), dumbbell flyes, dips, cable crossovers, peck deck flyes, etc.

leg extensions...squats....wall sits

yes