NCERT Solutions for Class 12 Biology

Welcome to the NCERT Solutions for Class 12 Biology. This page offers chapter-wise solutions designed to help students grasp key concepts easily. With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

• Chapter 1 Reproduction in Organisms

  We have seen a diversity of living organisms around us. Different varieties of organisms are some microscopic and huge animals but common in all is they have to reproduce for maintaining their species. Some question always arises in my mind, How do organisms reproduce, what are the ways? They reproduce in the same manner? Do they have some special organ for reproduction? Let cover all these in all this chapter.

• Chapter 2 Sexual Reproduction in Flowering Plants

  Maximum of as purchase plants or planets from the vendor and put into our garden. Have you ever thought about how the plant produces flowers, seeds and fruits? Plants can reproduce by vegetative propagule asexually but flower is part that is involved in sexual reproduction. For that they need to transfer the gamete known as pollination. Have you ever noticed that insects always visit the attracted flower. This is one of the steps followed by plants to attain Reproduction. In this chapter let us read and understand the sexual reproduction in plants.

• Chapter 3 Human Reproduction

  Adolescence is the period of stress and strome, during this phase of life there are many physical and hormonal changes occur that leads initiate sexual maturity. In male sperm production starts and in females eggs are released during the menstrual cycle. This is the basis for reproduction in humans. The sperm and ova come in contact, zygote formation occurs later implantation and finally a new individual is formed.

• Chapter 4 Reproductive Health

  Government and non governmental organisations initiated many programmes to aware people about family planning. There are different methods and devices through which a couple can use to avoid unwanted pregnancy. As we all know India has the second largest population due to which our country is facing many problems like unemployment, fetal death and maternal death and many more. There are many couples all over the world that are infertile. In this chapter we will read about many assisted reproductive technologies that are used to resolve infertility.

• Chapter 5 Principles of Inheritance and Variation

  Resemblance of kids to their parents are but Natural. Do all kids or progeny just look like their parents or they are morphologically completely different. Body shapes, height, colour of eye, hair pattern all are not always the same to the parent. This is due to sexual reproduction during Zygote formation; genes present in chromosomes are responsible for the characteristic feature. Mendel the father of genetics first time ever included statistics in biology and concluded the transfer of character from one generation to another explains that some factors are responsible for inheritance.

• Chapter 6 Molecular Basis of Inheritance

  Genetic is all about nucleic acid i.e. DNA and RNA. In DNA different genes are present that code for a particular character. Different scientist contributed their effort to explain that DNA is genetic material which is inherited from generation to generation. In this chapter we will understand the molecular level of what chromosomes are made of. How the gene are regulated, What is the human genome Project, DNA fingerprinting and many more.

• Chapter 7 Evolution

  Mystery yet to understand who came first? Egg or hen likewise who is the first man on the earth and so on. But there is certain evidence that explains the evolution of organisms into another. This is due to a change in environment which was best explained by Charles Drawin in his theory of Natural selection. Evolution, which is a slow and gradual change that leads into this modern era is explained by a few examples in this chapter.

• Chapter 8 Human Health and Disease

  Everyone is concerned about their health. Health is a state of body with social mental, physical and reproductively fit. If we are healthy we can be disease free. But disease free doesn't mean a healthy person. Diseases are caused by pathogens to fit with these and our body has an immune system. We will discuss how our body fights with these pathogens, and how antibodies are prepared for vaccines. One of the most important aspects is drugs and alcohol. Drugs if consumed, how it affects and its side effects.

• Chapter 9 Strategies for Enhancement in Food Production

  Our country is the second most populus country of the world for food and and supply to all is the most challenging task to achieve this many fool resources programme are inculcated to improve the production of food to make them available for all the country people. Each and every area of the food sector implemented different technology based on genetic engineering for large scale production, with quality of food is also the most focused area of concern. Tissue culture is major area of research for improvement of food resources.

• Chapter 10 Microbes in Human Welfare

  Yet we know that microbes cause several diseases but microbes are beneficial too. Microbes are used in medicine, beverage industry, food factories and many more. We will study that different microbes are used for preparing antibiotics, they are the best substitute for Antibiotic production in large quantities. Most importantly, we heard water is contaminated by microbes. But certain microbes are used in sewage plants to purify water.

• Chapter 11 Biotechnology Principles and Process

  Biotechnology is one of the best technologies for the well being of humans, which means biology and technology. The combinations of these created a broad area of research to modify the genome of organisms to make then transgenic. Till now many Genetically modified organisms are prepared successfully. In this chapter we will discuss the tools of recombinant DNA technology. Processes individual in making organisms transgenic. This process involves restriction enzymes, ligases plasmid for the recombinant DNA.

• Chapter 12 Biotechnology and its Application

  As we have already learnt biotechnology now in this chapter we will reveal more about its application in the field of agriculture, such as GMO plants e.g. Bt cotton Pest resistant plants, used also in medicine for production of insulin, Gene Therapy and molecular diagnosis and many more. Indian Government has set up organisations known as Genetic engineering approval committee who look after all the safety introducing for public welfare, so as to prevent the illegal use of this technology.

• Chapter 13 Organisms and Population

  Earth is a fascinating planet with diversity of organisms, their habitat, body structure, all physiological activity directly or indirectly depends on their environment. Earths tropic level have maximum number of diversity due to no seasonal change, climate remains constant whereas polar regions have minimum diversity due to very colder areas. Organisms adapted themselves according to their environment in polar regions animals have short external ears and limbs to reduce heat loss they undergo hibernation. In hotter climates the organism like snail, frog etc undergo aestivation so as to cope with the environment condition and continue the life. Organism interact with other for their requirement. This interaction is the basis of ecological balance on our planet.

• Chapter 14 Ecosystem

  Interaction between biotic and abiotic components creates our ecosystem and balance between these two components maintain our ecological balance, biogeochemical cycle. Flow of energy from one organism to another is continuous through the food chain and its network forming the food web. This is the beauty of our nature for maintaining life on this earth. In which major role is performed by decomposers, they are not mentioned in any of the food chain, without decomposers the ecological balance and nutrient cycle cannot be maintained. Decomposition is a slow process which involves certain steps such as fragmentation, leaching, catabolism, humification and mineralisation.

• Chapter 15 Biodiversity and Conservation

  On this amazing Earth millions of other species share with humans. The varieties are immense and their beauty reveals our nature making Earth a fascinating planet. Yet there are many species to be discovere. But these beautiful creatures have been badly affected by human activity. In the last few decades many of the species are extinct and some are threatened of extinction. This is a major area of concern for the sustainable management of the species and all Creatures of the earth, Government world wide initiated many programmes to conserve our biodiversity as each and every species values us.

• Chapter 16 Environmental Issues

  Advancement of technologies and increasing population has adverse effects on our environment day after day the pollution increases as more and more harmful chemicals are being used by humans for their benefit but they only see one face the other is more - dangerous to face that is leading to deadly disease and vanishing our biodiversity. This chapter explains the effect of pollution which leads to rise in temperature that is too deleterious to change in our environment. Many methods are developed to cope with the situation but yet more to come. Together we can resolve the problem of pollution & their effect.