CBSE 10th Science Answer Key 2026 (OUT): The Central Board of Secondary Education (CBSE) conducted the CBSE Class 10 Science Board Exam 2026 today at various exam centres accross the country. After the Mathematics exam held on 17 February 2026, students, today, appeared for another major subject that plays a crucial role in their overall results and deciding future stream. While the Mathematics paper received mixed reactions and was considered of higher difficulty level by many students, the CBSE Class 10 Science Exam 2026 is reviewed to be comparatively balanced and scoring.
The Science exam started at 10:30 AM and concluded at 1:30 PM. To help students evaluate their performance, we are providing the CBSE Class 10 Science Answer Key 2026 in this article. The expert-verified answer key will help students calculate their expected marks and analyse their performance accurately.
Answers for all sets of CBSE Class 10 Science Question Paper 2026 have been shared here. Students can download set-wise CBSE Class 10 Science answer keys PDF for free from the links shared here.
| LIVE Updates - CBSE Class 10 Science Paper Analysis 2026: Students' Reactions, Teachers' Review & Difficulty Level |
CBSE Class 10 Science Exam 2026: Highlights
Here are the key details that students must know about the CBSE Class 10 Science Board Exam 2026:
| Particulars | Details |
|---|---|
| Exam Name | CBSE Class 10 Science Board Exam 2026 |
| Board | Central Board of Secondary Education (CBSE) |
| Subject | Science (Code 086) |
| Exam Date | February 2026 |
| Exam Timing | 10:30 AM – 1:30 PM |
| Total Marks | 80 Marks (Theory) + 20 Marks (Internal) |
| Duration | 3 Hours |
| Answer Key | Out by Experts |
| Format | MCQs, Short Answer, Long Answer |
Also Check
CBSE Class 10 Maths (Standard) Answer Key 2026 - All Sets
CBSE Class 10 Maths (Basic) Answer Key 2026 - All Sets
CBSE Class 10 Science Answer Key 2026 (All Sets)
Our subject matter experts are analysing the CBSE Class 10 Science question paper to bring the answers ans solutions for the questions asked in today's exam. We have provided below answers for one question paper set and will update answers for other sets shortly.
CBSE Class 10 Science Answer Key 2026 (31/5/2) - By Experts
SECTION - A (Biology)
| Q. No | Correct Answer | Explanation |
| 1 | (C) Uterus |
Implantation of the fertilized egg (embryo) occurs in the lining of the uterus. |
| 2 | (D) Budding |
Yeast reproduces asexually through the process of budding. |
| 3 | (C) Guard cells |
Guard cells control the opening and closing of stomatal pores by changing shape. |
| 4 | (D)
|
This equation represents anaerobic respiration specifically in human muscle cells. |
| 5 | (B) DDT |
DDT is a synthetic chemical that does not break down naturally in the environment. |
| 6 | (C) 44+XY |
A human egg (22+X) fertilized by a Y-sperm (22+Y) results in a male zygote (44+XY). |
| 7 | (C) (i), (ii), (iii) and (iv) |
All listed factors contribute to the excessive generation of waste. |
| 8 | (A) |
Assertion & Reason are both true; muscles in the gut lining push food via peristalsis. |
| 9 | (A) |
Assertion & Reason are both true; asexual reproduction creates clones with minor DNA errors. |
Answer 10.
Part (A) Identification of Reflex Arc:
P: Receptor (Heat/Pain receptors in the skin)
Q: Sensory Neuron
R: Relay Neuron (located in the Spinal Cord)
S: Effector (Muscle in the arm)
OR
Part (B) Plant Hormones:
(i) Promote cell division: Cytokinins
(ii) Inhibition of growth: Abscisic acid
(iii) Detection of light: Auxins (which facilitate phototropism)
(iv) Wilting of leaves: Abscisic acid
Answer 11. Double Circulation in Human Heart
Double circulation involves the blood passing through the heart twice during one complete cycle through the body:
- Pulmonary Circulation: Deoxygenated blood is pumped from the right ventricle to the lungs, where it gets oxygenated and returns to the left atrium.
- Systemic Circulation: Oxygenated blood is pumped from the left ventricle to all body parts (except lungs) and returns as deoxygenated blood to the right atrium.
Answer 12. Leaf Structure and Photosynthesis
(i) P: Chloroplast; Role: It contains chlorophyll, which traps solar energy necessary for the process of photosynthesis.
(ii) Balanced Equation for Photosynthesis:
Answer 13.
(a) Plastic Bags:
Harmful Effect: They are non-biodegradable and cause soil/water pollution or choke animals.
Alternatives: Jute bags, paper bags, or cloth bags.
(b) Chemicals in Food Chain:
How they reach us: Chemicals in soil/water are absorbed by plants (paddy), which are then consumed by humans.
Phenomenon: Biological Magnification (Biomagnification).
Answer 14. Control and Coordination (Adrenaline)
(a) Gland: Adrenal Gland.
Hormone: Adrenaline.
(b) Body Responses:
Increased heart rate: To supply more oxygen to the muscles.
Increased breathing rate: Due to contractions of the diaphragm and rib muscles.
Answer 15.
(a) Bowman’s Capsule: A cup-shaped structure at the upper end of a nephron that collects the initial filtrate from the glomerulus.
(b) Filtration vs. Excretion: Most of the 180 L of filtrate is reabsorbed by the nephron tubules, leaving only 1-2 L as urine.
(c) Excretion: The biological process of removing harmful metabolic wastes from the body. It is necessary to prevent the toxic buildup of substances like urea.
OR
(c) Similarities (Lungs vs. Kidneys): Both are primary excretory organs and both possess a large surface area for exchange (alveoli in lungs, nephrons in kidneys).
Answer 16.
Part (A) Vegetative Propagation:
(i) Process: Vegetative Propagation.
(ii) Advantages: Plants can be grown faster than from seeds, and they are genetically identical to the parent.
(iii) Examples: Rose, Grapes, or Potato.
(iv) Regeneration Limitation: Complex organisms have specialized tissues and organs; they cannot regrow a whole body from a small piece because their cells are highly differentiated.
OR
Part (B) Post-Fertilization Changes:
(i) Structure Changes:
(a) Zygote: Develops into the Embryo.
(b) Ovule: Develops into the Seed.
(c) Ovary: Develops into the Fruit.
(d) Sepals: Usually wither and fall off.
(ii) Germination: The process by which a seed develops into a seedling under appropriate conditions of water, air, and temperature.
SECTION - B (Chemistry)
| Q. No | Correct Answer | Explanation |
| 17 | (D) C4H8 and C5H12 |
C4H8 is an alkene (Butene), while C5H12 is an alkane (Pentane). |
| 18 | (D) Al2O3 |
Aluminum oxide is amphoteric; it reacts with both acids and bases. |
| 19 | (C) The amount of H2 gas evolved is less. |
Acetic acid is a weak acid compared to sulfuric acid, so the reaction is slower. |
| 20 | (B) 2:1 |
Water (H2O) breaks into 2 parts Hydrogen and 1 part Oxygen by volume. |
| 21 | (D) |
CH3COONa is formed from a weak acid and strong base, making it Basic. |
| 22 | (C) C3H8 |
Propane (C3H8) is a saturated hydrocarbon (alkane) and does not undergo addition. |
| 23 | (D) Magnesium and Aluminium |
Both are above Hydrogen in the reactivity series and can displace it from HCl. |
| 24 | (A) |
Assertion & Reason are both true; the reaction of quicklime and water is highly exothermic. |
SECTION - C (Physics)
| Q. No | Correct Answer | Explanation |
| 30 | (A) Converging lens |
A reduced eyeball causes hypermetropia, which is corrected using a convex (converging) lens. |
| 31 | (A) 20 cm |
The focus (f) is 25 cm. For a virtual image in a convex lens, the object must be within the focal length (u<25 cm). |
| 32 | (D) |
Assertion is False, Reason is True. In a strong external field, the needle aligns with that field, not necessarily Earth's North-South. |
CBSE Class 10 Science Answer Key 2026 (31/5/3) - By Experts
SECTION - A (Biology)
| Q. No | Correct Answer |
| 1 | (D) |
| 2 | (B) |
| 3 | (A) |
| 4 | (C) |
| 5 | (B) |
| 6 | (C) |
| 7 | (C) |
| 8 | (A) |
| 9 | (B) |
SECTION - B (Chemistry)
| Q. No | Correct Answer |
| 17 | (D) |
| 18 | (C) |
| 19 | (B) |
| 20 | (D) |
| 21 | (D) |
| 22 | (D) |
| 23 | (C) |
| 24 | (A) |
SECTION - C (Physics)
| Q. No | Correct Answer |
| 30 | (A) |
| 31 | (A) |
| 32 | (D) |
Students can use this key to quickly check the 1-mark objective questions that appeared in today's paper.
Download CBSE Class 10 Science Answer Key 2026 PDF
| Question Paper Set | Answer Key PDF |
|---|---|
| Set 1 | Available Soon |
| Set 2 | Available Soon |
| Set 3 | Available Soon |
| Set 4 | Available Soon |
Note: The official answer key will be released by CBSE later; however, these expert solutions are highly accurate for immediate self-assessment.
Download CBSE Class 10 Science Question Paper 2026 PDF
Understanding the question pattern is essential for evaluating the answer key. We have compiled the question papers for all sets..
| Click here to Download CBSE Class 10 Science All Sets Question Paper 2026 PDF |
CBSE Class 10 Science Exam Pattern 2026
The CBSE Class 10 Science Question Paper 2026 follows the latest CBSE sample paper format issued by CBSE. This year, the paper is structured in a clearly divided format covering three major branches of Science:
-
Part A – Physics
-
Part B – Chemistry
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Part C – Biology
The question paper includes a variety of question types designed to test conceptual understanding and application-based learning.
Question Types & Marking Scheme
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Objective Type: Includes Multiple Choice Questions (MCQs) and Assertion-Reasoning questions worth 1 mark each.
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Short Answer Type: 2-mark and 3-mark questions requiring concise explanations or diagrams.
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Case-Based/Long Answer: 4-mark and 5-mark questions that test deep conceptual understanding and numerical problem-solving.
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Internal Choice: While all questions are compulsory, internal choices are provided in several sections to provide flexibility to students.
The CBSE Class 10 Science paper is a crucial milestone for students aiming for high percentages. With the Mathematics exam reported as difficult, the Science paper is expected to provide students with an opportunity to improve their overall scores.
The expert-verified CBSE Class 10 Science Answer Key 2026 provided here will help students quickly assess their performance and estimate marks. Set-wise PDF answer keys and question papers will be updated shortly after the exam concludes. By using the expert-verified CBSE Class 10 Science Answer Key 2026, students can reduce post-exam anxiety and get a realistic estimate of their marks. We recommend students cross-verify their answers with their NCERT textbooks for the most authentic understanding.
Students are advised to revisit this page regularly for latest updates and direct PDF download links for all sets.
Check Important Resources for Upcoming Exam Preparations
- CBSE Class 10 Syllabus for Board Exam 2026
- CBSE Class 10 Deleted Syllabus for Board Exam 2026
- CBSE Class 10 Sample Papers for Board Exam 2026
- CBSE Class 10 Important Questions for Board Exam 2026
- CBSE Class 10 Exam Pattern for Board Exam 2026
- CBSE Class 10 Practice Papers with Solutions (By CBSE Board)
- CBSE Class 10 Previous Year Question Papers (2020-2025)
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