<prompt> The neonatal kidney achieves concentrating ability equivalent to adults kidney by:One year of ageEighteen months of ageThree to six months of ageJust before pubey  <response>: Answer is A One year of age : Normal adult kidney can produce urine with an osmolalitv of greater than 1000 m Osmkg water. The healthy new born infant, subject to water deprivation for 10-14 hours can achieve an osmolality of only 500-700 m osm kg. This value increases gradually during the first few months and approximates to the adult value by about one year of age. 