NEET UG 2025 · Zoology · Question 125
NEET 2025 Zoology, question 125
Question 125 of the NEET 2025 paper (code 45) is a Zoology question from Excretory Products and their Elimination. Its idea, pH Maintenance by the PCT, was asked only this once in NEET 2017–2026. The NTA final answer key gives option 2.
Updated 2026-10-08
Q125 · Zoology
Which of the following diagrams is correct with regard to the proximal (P) and distal (D) tubule of the Nephron.
The figure, described in words
Four tubule diagrams (P and D segments) with upward arrows above (upper row) and below (lower row) the tubule wall for HCO3−, NaCl, H2O, H+, NH3, K+.
- 1[diagram: P – arrows HCO3−, NaCl (upper arrows); H+, H2O (lower arrows). D – NaCl, H2O, HCO3− (upper); K+, H+ (lower)]
- 2[diagram: P – arrows HCO3−, NaCl, H2O (upper arrows); H+, NH3 (lower arrows). D – NaCl, H2O, HCO3− (upper); K+, H+ (lower)]Official answer
- 3[diagram: P – arrows HCO3−, NaCl, H2O (upper arrows); H+, NH3 (lower arrows). D – H2O, HCO3− (upper); NaCl, H+ (lower)]
- 4[diagram: P – arrows NaCl, HCO3− (upper arrows); H+, H2O (lower arrows). D – NaCl, NH3 (upper); K+, H2O (lower)]
Official answer: option 2 · NTA final answer key
Same idea
The only question on pH Maintenance by the PCT
No other NEET paper from 2017–2026 tested this exact idea.
pH Maintenance by the PCT: every question and how it was framed
The chapter
Excretory Products and their Elimination in ten years of NEET
16 questions from 2017–2026, asked in 9 of 10 papers, about 1.5 a paper. Urine Formation alone had 13.