<prompt> Yoyo refluxDuplication of ureterPolycystic KidneyMellutary sponge KidneyPseudo kidney  <response>: Answer- A. Duplication of ureterReflux of the urine from one limb of the collecting system to the other limb, rather than down towards the bladder is called yo-yo reflux saddle refluxCause : Duplication of ureters, paial duplication ofureters, duplicate renal pelvis 