Lakhmir Singh Biology Class 9 Solutions Why do we Fall Ill (Chapter 5)

Lakhmir Singh Solutions for Class 9 Biology Chapter 5 contain clear explanations that will help you understand all the topics of the chapter. The concept of this chapter is not only important from the exam perspective but also from the perspective of real-life scenarios. In this chapter, you will learn all about diseases and what makes us feel sick. Solving the questions related to this chapter from the Lakhmir Singh Solutions for Class 9 book will make it easier for you to prepare for CBSE exams.

Our subject matter experts have explained every phenomenon and the processes in an interesting manner in the solutions. They adhere to the CBSE/NCERT syllabus so that our solutions can help you prepare for any upcoming tests in the school. All the solutions are written in simple language with examples.

Important Topics of Lakhmir Singh Solutions for Class 9 Biology Chapter 5

Chapter 5 of Lakhmir Singh Class 9 Biology Solutions covers every minute details of the important phenomenon of why we fall ill. It is a very interesting chapter to learn about the human body and its tendencies. Some of the important topics covered in this chapter are as follows:


It is a state of completely being socially, physically and mentally well to function properly.


It is basically any disturbance in the structure or function of any organ or part of the body. Diseases may be caused due to the attack of any bacteria or virus or by lack of a nutritious diet or the other reason could be a lack of public health services.

Types of Diseases

Diseases are of 2 types:

  1. Acute Disease like Flu, Common Cold, etc.
  2. Chronic Diseases like TB, Cancer, etc.


These are the medicine, drugs that block the biochemical pathways important for bacteria. They are used for diseases caused by bacteria. Antibiotics do not work against viral infections as the viruses do not have their own biochemical mechanisms but depend upon that of the host.

Means of Spread of Infectious Diseases

Infectious diseases spread from an infected person to a healthy person through the air, water, food, physical contact, etc.

Principles of Treatment 

The treatment of infectious diseases consists of 2 types. Their main work is to:

  1. Reduce the effects of the symptoms
  2. Kill the microbes which are causing the disease.

Principles of Prevention

There are 2 ways of prevention of infectious diseases:

  1. General ways of prevention
  2. Specific ways of prevention

Some Important Points to Remember

  • Health is a state of emotional, physical and social well-being
  • The health of an individual is dependent on his/her physical surroundings.
  • Diseases are classified as acute or chronic, depending on their duration. 
  •  The disease may be due to infectious or non-infectious causes. 
  • The category to which a disease-causing organism belongs decides the type of treatment.
  •  Infectious agents are spread through the air, water, physical contact or vectors.
  • Prevention of disease is better than its successful treatment. 
  •  Infectious diseases can be prevented by public health hygiene measures that reduce exposure to infectious agents.
  •  Effective prevention of infectious diseases in the community requires that everyone should have access to public hygiene and immunization.

Benefits of Lakhmir Singh and Manjit Kaur Solutions Class 9 Chapter 5

Lakhmir Singh Solutions for Class 9 Chapter 5 provides all the expert-designed solutions which are accurate and verified. Instasolv is a platform that will help you get exam-ready by providing you with all the relevant study material. Our team simplifies the CBSE syllabus and presents it in the form of solutions which makes it easy for students to understand the content of their syllabus. Lakhmir Singh and Manjit Kaur Solutions by Instasolv will work as a reference guide for you which has solutions to your every query and doubt. Our team keeps on updating the content from time to time so as to provide you with the latest study materials.