( A ) Sweat produced by the sweat glands is a watery fluid containing NaCl, small amounts of urea, lactic acid, etc.
( B ) Lungs remove large amounts of CO2 (18 litres/day) and also significant quantities of water every day
( C ) all of the above
( D ) Liver secretes bile-containing substances like bilirubin, biliverdin, cholesterol, degraded steroid hormones, vitamins and drugs. Most of these substances ultimately pass out alongwith digestive wastes