In this article we are providing the detailed and accurate NCERT Exemplar Solutions for Class 12 Biology chapter 8, Human Health and Diseases. Each solution is explained in a way to help students easily understand concepts used in it.
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Students, who are having trouble finding the right and simple answers for the NCERT Exemplar Problems for chapter- Locomotion and Movement, should refer the answers given here. You will find here the most appropriate answers which include all the basic theories and terms of Biology. These solutions have been collated in the form of PDF which students can download for free of cost and refer the same when required.
Few problems along with their solutions from this chapter are given follows:
Q. The organisms which cause diseases in plants and animals are called
Ans. (a) pathogens
The organisms which cause diseases in plants and animals are called pathogens.
Vectors are the carriers of pathogens.
All the insects and worms do not cause diseases.
Q. The genes causing cancer are
(a) structural genes
(b) expressor genes
(d) regulatory genes
Ans. (c) oncogenes
Normal cells have genes called cellular oncogens or proto-oncogenes which are present in inactivated state, but under certain conditions (like mutation) these get transformed to cancer causing oncogens which are active.
On the other hand, structural genes, expressor gene and regulatory genes are responsible for regulation of gene expression.
Q. Why is mother's milk considered the most appropriate food for a new born infant?
Ans. Mother’s milk during initial days after delivery is called colostrums. It contains several antibodies (especially IgA) which are absolutely essential for developing resistance for many diseases in the new-born babies.
Q. What does the term 'memory' of the immune system mean?
Ans. When the body encounters a pathogen for the first time, it mounts an immune response by generating antibodies. This response is of low intensity. Subsequent encounter with the same pathogen elicits a highly intensified secondary response.
This is ascribed to the fact that our body appears to have memory of the first encounter. This type of secondary immune response is elicited by memory T-cells, B-cell which keeps ready to mount a rapid and vigorous attack as soon as the same pathagen infects the body again.
Q. For an organ transplant, it is an advantage to have an identical twin. Why?
Ans. For an organ transplant, it is an advantage to have an identical twin because the organ will have same surface markers and therefore, the recipient's immune system will not identify it as foreign and will not react against it. In case of different surface markers, the immune system starts a reaction, kills the foreign tissue or rejects it.
Find below the links to download Class 12 Biology NCERT Exemplar Solutions for chapter 8 - Human Health and Diseases:
Link to Download PDF
Multiple Choice Questions
Very Short answer type questions
Short answer type questions
Long answer types questions
Class 12 Biology NCERT Exemplar Problems:
Class 12 Biology NCERT Exemplar problems are a very good resource for preparing the critical questions like Higher Order Thinking Skill (HOTS) questions. Every year, many questions from the NCERT Exemplar are directly asked in the board exams as well as the medical entrance exams. So, it’s very important for students to practice the NCERT exemplar problems to prepare well for the boards and the competitive exams.
Main topics discussed in Class 12 Biology, Chapter 8- Human Health and Diseases, are:
Download the complete NCERT Exemplar book from the following link:
Note: Once you are done with all the NCERT Exemplar problems, refer the solutions given above in this article to check the correctness of your own solutions and know the right way to get the perfect answers.