Gynaecology & Obstetrics Coaptation is A Urethral mucosal approximation. B Adaptation of bladder to large volumes of filtrate. C Stretch of urethra while voiding. D Constriction of ureters in response to low volumes of urine. 💡 Explanation Coaptation is ✓ Correct Answer: A. Urethral mucosal approximation.