el 99 % del cuerpo only thing chemistry.about.com... mostly water Did you know that humans are about 18% carbon? i don't think sO 18% of human body weight trace amounts of silica Did you know that humans are about 18% carbon? Element in the Human Body About:Chemistry 18% of human body weight About:Chemistry trace amounts of silica About only thing trace amounts of silica About Did you know that humans are about 18% carbon? about 65% water What are the elements in the human body? 18% of human body weight What are the elements in the human body?