The best approximation of the true outer boundary of the continents is the seaward edge of the _

answer; the best approximation of the true outer boundary of the continents is the seaward edge of

(continental shelf); /// is your correct answer;

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.