CBSE Class 12 Biology 2025-26: Top 100 MCQs with Answers for Last Minute Revision - Free PDF

The CBSE Class 12 Biology examination is scheduled to be held on March 27, 2026. Section A of the examination is entirely based on MCQs (Multiple Choice Questions)—including Assertion-Reason type questions. Therefore, preparing thoroughly for MCQs is crucial to achieve a high score.

In accordance with the new CBSE syllabus for the 2025-26 academic session, we have compiled a set of the 100 most important MCQs, complete with their answers. These questions cover all the key units of the syllabus.

These questions are designed based on a competency-based and application-oriented pattern, with the primary objective of emphasizing conceptual clarity and factual accuracy. Be sure to attempt these 100 MCQs before the examination to boost your confidence.

To further strengthen your preparation, you can download PDFs from the table provided below.

Top 100 MCQs CBSE 12 Biology Exam 2026 with Answers

1. In which of the following plants are both male and female flowers born on the same plant and the mode of pollination can be geitonogamy or xenogamy?

(A) Papaya

(B) Date Palm

(C) Maize

(D) Spinach

2. Which one of the following hormones is secreted by the human placenta that helps in the maintenance of pregnancy?

(A) Relaxin

(B) Human Chorionic Gonadotropin

(C) Oxytocin

(D) Human Placental Lactogen

3. The periodic abstinence by a couple for family planning should be from:

(A) Day 5 to 10 of menstrual cycle

(B) Day 13 to 15 of menstrual cycle

(C) Day 10 to 17 of menstrual cycle

(D) Day 16 to 20 of menstrual cycle

4. Select the incorrect match from the following:

        Human Karyotype             Characters

(A)   45+ XX                              Broad palm with characteristic palm crease

(B)   44+XXY                             Overall feminine development

(C)   44+XO                               Sterile females as ovaries are rudimentary

(D)   44+XY                                Normal male

5. You know that there are twenty different types of naturally occurring amino acids and four different types of bases in the DNA. A combination of 3 such bases code for a specific amino acid. If instead there are 96 different amino acids and 12 different bases in the DNA, then the minimum number of combination of bases required to form a codon is :

(A) 6

(B) 8

(C) 2

(D) 4

Download PDF CBSE 12 Biology Top 100 MCQs with Answers

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👉 CBSE Class 12 Study Materials

CBSE Class 12 study material includes latest syllabus, sample papers, NCERT books and solutions, previous year question papers, chapter-wise important questions, case study questions, assertion-reason questions, and competency-based questions — all updated as per the latest CBSE board exam pattern.