Good afternoon sir/Madam as per allen answer key bio question 6 answer it was 4, but official key answer is 2, can I challenge for this
You may challenge it, but it won't help. This year, 4 questions, 3 from biology and 1 from physics are being debated as they were different in the NTA and Allen answer keys.
But NTA has chosen the correct or more appropriate options so challenging the answer may not make a difference. Best wishes!