Urine is produced in

1. At night, Plants intake __________ and release __________.

A. Oxygen – Carbon dioxide

B. Carbon dioxide – Oxygen
C. Oxygen – Carbon monoxide
D. Carbon monoxide – Oxygen

2. Urine is produced in __________.

A. Kidneys

B. Lungs
C. Large intestine
D. Liver

3. Blood is cleaned by __________.

A. Lungs
B. Liver
C. Heart

D. Kidney