NCERT Solutions for Class 12 Biology are designed to guide students through every chapter of the textbook with clear and accurate answers. The book contains 13 chapters covering important topics such as reproduction, genetics, evolution, human health, microorganisms, biotechnology and ecosystems.
These NCERT solutions simplify complex biological processes into easy explanations using diagrams and flowcharts. This makes it easier for students to learn concepts and retain them for a longer time. Shiksha Nation’s solutions are a great resource for board exam preparation, helping students strengthen their understanding of important Biology concepts through a structured approach.
NCERT Solutions for Class 12 Biology Chapter wise 2026 27
| S.No. | Chapter Name & Topic |
| 1 | Chapter 1 - Sexual Reproduction in Flowering Plants |
| 2 | Chapter 2 - Human Reproduction |
| 3 | Chapter 3 - Reproductive Health |
| 4 | Chapter 4 - Principles of Inheritance and Variation |
| 5 | Chapter 5 - Molecular Basis of Inheritance |
| 6 | Chapter 6 - Evolution |
| 7 | Chapter 7 - Human Health and Disease |
| 8 | Chapter 8 - Microbes in Human Welfare |
| 9 | Chapter 9 - Biotechnology : Principles and Processes |
| 10 | Chapter 10 - Biotechnology and its Applications |
| 11 | Chapter 11 - Organisms and Populations |
| 12 | Chapter 12 - Ecosystem |
| 13 | Chapter 13 - Biodiversity and Conservation |
Chapter-wise NCERT Solutions for Class 12 Biology Overview
Chapter 1 - Sexual Reproduction in Flowering Plants
The first chapter explains the process of sexual reproduction in flowering plants and the structures involved in it. Students learn about the morphology and development of the flower, including the male and female reproductive organ. The chapter discusses microsporogenesis and megasporogenesis, the formation of pollen grains and embryo sacs, pollination mechanisms and the adaptations that facilitate pollination.
Students also study pollen-pistil interactions, double fertilization, post-fertilization events such as endosperm and embryo development and the formation of seeds and fruits. It also includes important concepts such as apomixis and polyembryony.
Chapter 2 - Human Reproduction
This chapter explains the process of human reproduction and the biological mechanisms involved in the continuation of the species. Students learn about the structure and functions of the male and female reproductive systems, including the testes, ovaries and glands. The chapter discusses gametogenesis, the menstrual cycle and the hormonal regulation of reproductive processes.
Students also study fertilization, implantation, pregnancy, embryonic and fetal development, parturition and lactation. It talks about important concepts such as the placenta, reproductive hormones and the stages of human development.
Chapter 3 - Reproductive Health
Chapter 3 discusses reproductive health and the measures necessary to ensure physical, emotional and social well-being related to reproduction. Students learn about the importance of reproductive health, family planning and population stabilization. The chapter includes various contraceptive methods, including natural, barrier, intrauterine, hormonal and surgical methods.
Students study sexually transmitted infections, their prevention and control and the significance of awareness and safe reproductive practices. It also explains infertility, assisted reproductive technologies including IVF, ZIFT, GIFT, ICSI and surrogacy.
Chapter 4 - Principles of Inheritance and Variation
This chapter explains the fundamental principles of genetics and how traits are transmitted from one generation to the next. Students learn about the work of Gregor Mendel, including Mendel's laws of inheritance.
The chapter discusses monohybrid and dihybrid crosses, chromosomal theory of inheritance, linkage and recombination, and the role of chromosomes in heredity. Students also study sex determination, sex-linked inheritance, pedigree analysis, mutations and genetic disorders such as haemophilia, colour blindness, sickle-cell anaemia and thalassaemia.
Chapter 5 - Molecular Basis of Inheritance
This chapter explains the molecular mechanisms through which genetic information is stored, transmitted and expressed in living organisms. Students learn about the structure of DNA and RNA, the experiments that established DNA as the genetic material and the contributions of scientists such as James Watson, Francis Crick and Rosalind Franklin.
The chapter discusses DNA replication, transcription, the genetic code, translation and the regulation of gene expression. Students also study the Human Genome Project, DNA fingerprinting and their applications in medicine, forensics and biotechnology. It also discusses mutations, operons and gene regulation.
Chapter 6 - Evolution
Chapter 6 explains the origin and evolution of life on Earth and the mechanisms that drive biological change over time. Students learn about theories concerning the origin of life, fossil evidence, comparative anatomy, embryology and molecular evidence that support evolution.
The chapter discusses the contributions of scientists such as Charles Darwin and Alfred Russel Wallace, explaining concepts such as natural selection, adaptive radiation, genetic drift, gene flow and speciation. Students also study the evolution of humans and the role of variation and mutation in evolutionary processes.
Chapter 7 - Human Health and Disease
In this chapter, students learn about the difference between health and disease, the causes of infectious and non-infectious diseases and the role of pathogens such as bacteria, viruses, protozoa, fungi and helminths. The chapter discusses common diseases including malaria, amoebiasis, ascariasis, typhoid, pneumonia, common cold and fungal infections.
Students also study the human immune system, innate and acquired immunity, antibodies, vaccination, allergies and autoimmune disorders. It also explains cancer, HIV/AIDS, drug and alcohol abuse, and their effects on society.
Chapter 8 - Microbes in Human Welfare
This chapter discusses the beneficial roles of microorganisms in human life and the environment. Students learn about the use of microbes in household products such as curd, cheese, bread and fermented beverages. The chapter explains how microorganisms are employed in industrial production for manufacturing antibiotics, organic acids, enzymes and bioactive molecules.
Students also study the role of microbes in sewage treatment, biogas production and waste management. It includes important concepts such as biological control of pests and diseases, biofertilizers and the use of microorganisms in sustainable agriculture.
Chapter 9 - Biotechnology : Principles and Processes
Chapter 9 discusses the fundamental principles and techniques of biotechnology and their applications in modern science. Students learn about the concepts of genetic engineering, rDNA technology and the tools used in biotechnology, including restriction enzymes, DNA ligase, cloning vectors and competent host cells.
The chapter explains the processes involved in gene cloning, DNA insertion, amplification using polymerase chain reaction and the production of recombinant proteins. Students also study the steps of recombinant DNA technology, bioreactors and downstream processing.
Chapter 10 - Biotechnology and its Applications
This chapter explains the practical applications of biotechnology in agriculture, medicine, industry and environmental management. Students learn about genetically modified organisms and their uses, including insect-resistant crops such as Bt cotton and crops developed for improved nutritional quality. The chapter discusses the production of therapeutic products through genetic engineering, such as human insulin, vaccines and gene therapy.
Students also study molecular diagnosis techniques, including PCR and ELISA, which are used for the detection of genetic disorders and infectious diseases. It includes important topics such as transgenic animals, biopiracy and biosafety issues.
Chapter 11 - Organisms and Populations
This chapter explains the interactions between organisms and their environment and explains how these interactions influence the distribution, abundance and survival of species. Students learn about the concept of populations, population attributes such as birth rate, death rate, age structure, sex ratio, population density and population growth. The chapter discusses how organisms adapt to environmental factors including temperature, water, light and soil.
Students also study various ecological interactions such as mutualism, commensalism, parasitism, predation, competition and amensalism. It also explains important concepts such as population growth models, carrying capacity and life-history strategies.
Chapter 12 - Ecosystem
This chapter explains the structure and functioning of ecosystems and the interactions between living organisms and their physical environment. Students learn about the components of an ecosystem, including abiotic factors (such as light, temperature, water, and nutrients) and biotic factors (producers, consumers, and decomposers). The chapter discusses energy flow through ecosystems, food chains, food webs, ecological pyramids and productivity.
Students also study decomposition, nutrient cycling, ecological succession and ecosystem services. It also explains grazing and detritus food chains, biogeochemical cycles and the role of ecosystems in maintaining environmental balance.
Chapter 13 - Biodiversity and Conservation
The last chapter discusses the diversity of life on Earth and the importance of conserving biological resources. Students learn about the concept of biodiversity, its levels and patterns of biodiversity across different regions. The chapter shows the importance of biodiversity in maintaining ecological balance and supporting human well-being.
Students study threats to biodiversity, including habitat loss and fragmentation, overexploitation, invasive species, co-extinctions and environmental degradation. It also discusses biodiversity hotspots, endangered species, extinction and conservation strategies.
