CBSE Class 12 Biology Previous Year Question Papers with Solutions (2020-2026)

CBSE also lists the March 2026 Biology paper and its marking scheme, as ZIP files, on its question paper page and marking scheme page.

CBSE Class 12 Biology 2026 question paper: unit-wise marks

Here are the 33 questions of the March 2026 Set 1 paper (code 57/1/1), each placed under its unit in the 2026-27 syllabus:

• Reproduction: 16 marks (Q1, 3, 12, 18, 22, 25, 31)
• Genetics and Evolution: 20 marks (Q8, 10, 13, 20, 23, 24, 30, 32)
• Biology and Human Welfare: 12 marks (Q2, 15, 17, 26, 33)
• Biotechnology and its Applications: 11 marks (Q9, 11, 14, 19, 27, 28)
• Ecology and Environment: 10 marks (Q4, 6, 7, 16, 21, 29)
• Not assigned: 1 mark (Q5, on how the pomato was made by fusing protoplasts, a topic the current syllabus does not name)

Source: CBSE Class 12 Biology question paper 57/1/1 (March 2026) and the 2026-27 curriculum, Gradehunt analysis.

If you count the pomato question under Biotechnology, each unit lands exactly on CBSE's weightage of 16, 20, 12, 12 and 10 marks. Genetics and Evolution is the largest unit and had a question in every section, including a 5-mark answer on the DNA double helix or transcription.

What else the 2026 Biology paper shows

• Seven questions were built around a picture, a chart or a drawing: chromosome pairing (Q8), an ecological pyramid (Q21), a pedigree chart (Q23), the megasporangium you draw and label (Q25), a gel electrophoresis setup (Q28), barnacles on a rocky shore (Q29) and bar graphs of genetic crosses (Q30).
• Several questions describe a situation and ask you to apply a concept: a farmer spraying Bt spores on one of two corn fields (Q27), and three couples who need a suitable assisted reproductive technology (Q31, second option).
• Eight questions offered an internal choice: three of the five 2-mark questions (Q18, 20, 21), one sub-part of each case-based question and all three long answers. The MCQs and 3-mark questions had none.
• Set 2 reused 21 of Set 1's 33 questions, worth 49 marks, in a different order. Solving one set well covers a good part of the others.

Biology paper pattern and time per mark

The theory paper is 70 marks in 3 hours, with 15 minutes of reading time first. It has 33 questions in five sections: 16 one-mark MCQs (four of them assertion-reason), five 2-mark, seven 3-mark, two 4-mark case-based and three 5-mark questions. Practicals carry the other 30 marks.

That gives you about 2½ minutes per mark, or roughly 13 minutes for each 5-mark answer. A labelled diagram takes longer than students plan for, so keep 5 minutes in hand for Q25-type drawing questions.

Searching for the Biology sample paper with solutions? CBSE's 2026-27 sample paper and marking scheme are free on cbseacademic.nic.in. The sample paper notes that the question paper design and assessment pattern have not changed for 2026-27.

How the 2026 Biology marking scheme gives marks

• Q25, megasporangium diagram (3 marks): ½ for each of six correct labels. A neat drawing with three labels earns 1½.
• Q22, pollen viability (3 marks): ½ for answering "No", 1 for each of two examples, and ½ for how pollen banks store pollen (in liquid nitrogen at -196°C).
• Q24, Hardy-Weinberg (3 marks): the derivation is split into four ½-mark steps, then ½ for each factor that disturbs the equilibrium.
• Q27, Bt corn (3 marks): ½ for naming the gene, three ½-mark points on how the toxin kills the larva, and 1 for explaining the GM plant's resistance.

Marks come for named terms, examples and each step of a process. An answer that explains the idea in general words but never names the gene, the example or the label loses most of them. The scheme's instructions also say that if you attempt both options of a choice question, both are marked and the higher score counts.

Which Biology previous year papers to solve first

• Write 2026 Set 1 in three hours, with every diagram drawn. Then answer only the new questions in Sets 2 and 3.
• Move on to 2025 and 2024, then 2023 and 2020.
• Use the 2022 papers for chapter practice. That exam was held term-wise and was much shorter.
• Check each answer against the solution and underline the terms the marking scheme rewards. Learn those terms the way they are written there.

For practice by chapter, Gradehunt's 10 Years Solved Papers (PYQ) for CBSE Class 12 Biology gathers the board questions from 2016 to 2026 under each chapter of the 2026-27 syllabus, with the exam year on every question and the marks for each point in the solutions.

Past papers for other Class 12 science subjects

Solved past papers for Physics, Chemistry and Maths are also on Gradehunt.