RBSE Solutions For Class 12 Biology Chapter 40: Important and common Human Diseases | Textbook Important Questions & Answers

RBSE Class 12 Biology Chapter 40 – Important and Common Human Diseases. In this chapter, students can learn in detail about the different types of health disorders, congenital diseases, acquired diseases, infectious diseases, non – infectious diseases, deficiency diseases, non-deficiency diseases, causes of cancer, types of tumours and types of allergy. It also deals with infections, nutritional disorders, biochemical disorders, lifestyle disorders, mechanical disorders, degenerative disorders, genetic disorders, mental disorders, diseases caused by bacteria, diseases caused by viruses, diseases caused by protozoa, diseases caused by helminths and much more.

These important questions help students to perform exceptionally well in their exams. By practising these important questions, students can analyze their preparation, get a thorough knowledge about all the important terminologies and perform their best in the examinations.

RBSE Solutions for Class 12 are the best study material for both class assignments and other board examinations. By practising these important questions, students can gain deep knowledge about the topics explained in this chapter and also help them to be well prepared for their upcoming examinations.

RBSE Class 12 Biology Chapter 40 Important Questions

RBSE Biology Chapter 40: MCQ Type Questions

Q.1. Which of the following diseases has been eradicated?

(a) Polio

(b) Smallpox

(c) Rinderpest

(d) All of the above

Sol: (d) All of the above.

Q.2. Which of the following is a viral disease?

(a) Filariasis

(b) Leprosy

(c) Influenza

(d) Diphtheria

Sol: (c) Influenza.

Q.3. Which of the following bacteria causes plague?

(a) Yersinia pestis

(b) Yersinia enterocolitica

(c) Yersinia pseudotuberculosis

(d) None of the above

Sol: (a) Yersinia pestis.

Q.4. Which of the following agents are responsible for Elephantiasis?

(a) Flatworms

(b) Filarial worms

(c) Tapeworms

(d) None of the above

Sol: (b) Filarial worms.

Q.5. Which of the following is a genetic disease?

(a) Haemophilia

(b) Colour blindness

(c) Sickle cell Anaemia

(d) All of the above

Sol: (d) All of the above.

Q.6.Which of the following diseases are treated only in its initial stages?

(a) Cancer

(b) Asthma

(c) Allergies

(d) Emphysema.

Sol: (a) Cancer.

Q.7. Guinea-Worm disease is caused by _________.

(a) Ascaris

(b) Enterobius

(c) Taenia

(d) Dracunculus

Sol: (d) Dracunculus.

Q.8. Malaria is caused by the biting of _________mosquito.

(a) Culex mosquitoes

(b) Male Anopheles

(c) Female Anopheles

(d) Aedes mosquitoes

Sol: (c) Female Anopheles.

Q.9. Kala-azar disease is caused by _________.

(a) Leishmania

(b) Plasmodium

(c) Trypanosoma

(d) Entamoeba histolytica

Sol: (a) Leishmania.

Q.10.Which of the following viruses causes AIDS in humans? 

(a) HIV

(b) Rabies

(c) Poliovirus

(d) Influenza viruses

Sol: (a) HIV.

RBSE Biology Chapter 40: Short and Long Answer Type Questions

Q.1. What is a disease?

Sol: The diseases can be simply defined as a medical condition that deteriorates the normal functioning of the cells, tissues, and organs. There are numerous diseases which vary in their signs, symptoms and causes.

Q.2.What are non-infectious diseases?

Sol: Diseases that do not spread from person to person are called non-infectious diseases. Cancer is a major non-infectious disease. Other examples of non-infectious diseases include diabetes, thyroid, osteoporosis, asthma, heart-related disorders, cataracts, Alzheimer’s and other deficiency disorders.

Q.3. What is Pathology?

Sol: The branch of medicine which mainly deals with the study of disease, the nature of diseases, its causes, its symptoms, its cure, diagnosis, etc.is termed as Pathology.

Q.4. What are infectious agents?

Sol: Infectious agents are all around us, and they come in different shapes and sizes. They can be categorized based on some common characteristics. Some are single-celled animals such as fungi, bacteria and viruses. Other multicellular organisms such as worms are known to cause diseases too.

Q.5. What is hypertension?

Sol: Hypertension is also known as high blood pressure. It is a serious, chronic health problem related to the pressure or the force exerted by the blood against the walls of the blood vessels. It is quite common in today’s lifestyle and affects nearly one billion people worldwide.

Q.6. What are the diseases caused by helminths?

Sol: Helminths are worm-like parasites that survive by living inside the host cells. These parasites gain nourishment and protection from the host cells and cause harm to the host cells. The diseases caused by helminths are:

  • Ascariasis – caused by a roundworm Ascaris.
  • Enterobiasis – caused by a pin or seat worms.
  • Dracunculiasis – caused by guinea worms.
  • Taeniasis – caused by the various species of tapeworm.

Q.7. What are contagious diseases? Give examples.

Sol: Contagious diseases are the type of communicable diseases, which is caused by direct contact with an infected person. Ringworm, conjunctivitis, scabies, plague, skin allergies are some examples of contagious diseases.

Q.8. What are infectious diseases?

Sol: Infectious diseases are the diseases caused by pathogenic microorganisms namely virus, bacteria, fungi, and parasite. These diseases can be communicable or noncommunicable. These can be transmitted by animals, humans or insects.

Q.9. What is the difference between AIDS and HIV


Acquired Immunodeficiency Syndrome (AIDS) is the disease. It is a condition acquired only after the contraction of HIV. AIDS is the most severe phase of HIV infection. People with AIDS have completely damaged immune systems, which may also result in an increasing number of severe diseases, called opportunistic infections.


Human Immunodeficiency Virus(HIV) is a virus and like other viruses, can spread from person to person. It is the causal factor for AIDS in humans. The virus is incapable of killing a host by itself.

Q.10. List of a few infectious diseases:

Sol: Polio, rabies, mumps, dengue, plague, malaria, anthrax, cholera, measles, HIV/AIDS, hepatitis A, hepatitis B, hepatitis C, tuberculosis, yellow fever, typhoid fever are examples of few infectious diseases caused by infectious agents.

Q.11. Write the differences between communicable and non-communicable diseases. diseases

Sol: Both communicable diseases and non-communicable diseases cause harm to humans. The main differences between the communicable and non-communicable diseases are their mode of causes.

Differences between communicable and non-communicable diseases:

Communicable diseases Non-communicable diseases
Diseases spread from one to another person. Diseases cannot be transmitted from one to another person.
Virus and bacteria are the main causing agents. No agents are involved in these diseases.
Infectious pathogens and vectors transmit these diseases. Causatives are allergies, malnutrition, internal factors, lifestyle changes, environmental changes, etc.
Cannot be inherited from one generation to another. Can be inherited from one generation to another.
It is an acute type of disease. It is a chronic type of disease.
The treatments include traditional methods and therapies. The treatments include surgically or specialized methodologies.
Examples include AIDS, Typhoid, Tuberculosis, Malaria, Cholera, etc. Examples include Allergies, cancer, heart diseases, diabetes, etc.

Q.12.Write a short note on amoebiasis.

Sol: Amoebiasis is also known as amoebic dysentery. It is an illness or a parasitic infection of the colon caused by a parasite Entamoeba histolytica. The parasite Entamoeba histolytica invades the cells of the intestines and survives by living inside the host cells. This parasite produces eggs (cysts) which are passed out of the body in the stool. It results in diarrhoea and colitis.

Causes of Amoebiasis

A person becomes infected with E. histolytica by swallowing cysts of the parasite. This can occur in the following ways:

  • Poor personal hygiene.
  • Drinking contaminated water.
  • Cooking and washing food in contaminated water.
  • Eating food which has been prepared by an infected person.
  • By an oral-anal sexual contact with a person infected with E. histolytica.
  • Amoebiasis occurs in people who live in areas with poor sanitary conditions.

Symptoms of Amoebiasis

  • Fever.
  • Chills.
  • Nausea.
  • Weight loss.
  • Abdominal discomfort.
  • Diarrhoea that may include blood or mucus with periods of constipation.

Treatment of Amoebiasis

Symptomatic amoebiasis should be treated with a systemically-active compound such as metronidazole, followed by a luminal amoebicide to eliminate any surviving organisms in the colon. Metronidazole is not recommended for use during the first trimester of pregnancy.

Asymptomatic carriers should be treated with a luminal amebicide in order to reduce the risk of transmission and protect the patient from symptomatic amebiasis.

Q.13. Write a short note on cancer.

Sol: Cancer is a complex disease, which may occur in any part of the body.

It is one of the most dreadful diseases, which affects over 11 lakh people every year in India alone and worldwide there are more than 10 million people diagnosed with cancer. Uncontrolled cell-division occurs when a process called contact inhibition fails, which results in the cause of cancer in humans.

Causes of cancer

Many factors are attributed to causing cancer. The most probable factors include:

  1. Physical factors – Ionizing radiation such as X-rays and gamma rays.
  2. Chemical factors – Such as tobacco and smoke.
  3. Biological factors – Viral oncogenes, proto-oncogenes and cellular oncogenes.

Diagnosis of Cancer

The detection and diagnosis of cancer are very important before it spreads to other parts of the body. Identification of cancer genes is very valuable to prevent cancer.

The following methods are used to detect cancer –

  1. Biopsy.
  2. Radiography technique.
  3. Computed tomography.
  4. Magnetic resonance imaging.
  5. Molecular biology techniques.

Treatment of Cancer

There are three types of treatment available for cancer.

  1. Surgery – Surgically removing localized cancerous mass (Effective for benign tumours)
  2. Radiation therapy – In this therapy, radiation is used to kill the cancer cells.
  3. Chemotherapy – Chemotherapeutic drugs are used to kill cancer cells.

Q.14.Write a short note of asthma.

Sol: Asthma is also called chronic respiratory disease. It causes many breathing difficulties such as coughing, wheezing and shortness of breath. This syndrome is characterized by inflammation in airways, causing difficulty in breathing.

Causes of Asthma

There are several factors responsible for triggering asthma attacks. The causes of asthma are still unknown, however, it is known to be triggered by environmental factors. Known triggers of asthma attacks are:

  • Smoking.
  • Sinusitis.
  • Allergies.
  • Pollution.
  • Medication.
  • Dust and dust mites.
  • Vehicular and industrial exhaust.
  • Respiratory infections caused by the common cold.

Symptoms of Asthma

The symptoms of asthma are generally mild. However, it can quickly become severe to life-threatening if neglected. The most common symptoms of an asthma attack are:

  • Wheezing.
  • Tiredness.
  • Rapid breathing.
  • Breathing problems.
  • Persistent coughing.
  • Difficulty in talking.
  • Sweaty and pale face.
  • Pressure or tightness on the chest.

Treatment for Asthma

There are various types of asthma and the treatment varies from person to person, which are based on the symptoms and causes.

Asthma is a long-term syndrome which has no permanent cure with today’s medical technologies. However, the condition can be controlled by avoiding things that worsen asthma attacks. Use of certain medicines and inhalers can avoid the worsening of the symptoms.

Q.15. What are communicable diseases?

Sol: Diseases which can be transferred from one individual to another are called communicable diseases. These diseases are caused by the invading of pathogens such as viruses and bacteria. These diseases spread from one to another person through water, air etc.

Communicable diseases

Q.16. What are the practical ways to control the spread of infectious diseases?

Sol: A few practical ways which can be practised for preventing the spread of infections are:

  • Use of antibiotics.
  • Maintaining proper hand hygiene.
  • Vaccination – one of the most effective ways.
  • Avoid travelling or going to work when you fall ill.
  • Maintain hygiene both in the bathroom and in the toilet area.
  • Avoid sharing personal belongings such as a razor, drinking glass, toothbrush, comb, etc.
  • Keeping the kitchen clean by washing all the used utensils, cooking area before and after preparing each food.
  • While visiting patients in hospitals, it is recommended to wear a mask, gown and if possible make use of sanitizing gels to prevent infection.

Q.17. What are the types of infectious diseases?

Sol: Infectious diseases are the diseases caused by pathogenic microorganisms namely virus, bacteria, fungi and parasite. These diseases can be communicable or noncommunicable.

There are various types of infectious diseases caused by different pathogens. These diseases are mentioned below:

Viral Infections

There are millions of viruses existing in the world. They are the main cause of viral infections such as common cold, influenza, AIDS, etc.

Bacterial Infections

There are numerous bacterial strains some of which cause diseases. The harmful bacteria cause diseases while good and beneficial bacteria present in our body destroys harmful and diseases causing bacteria and prevent diseases. Cholera, tuberculosis, diphtheria, typhoid are some of the infectious diseases caused by bacteria.

Fungal Infections

A fungus decomposes and absorbs organic material with the help of an enzyme. If the good bacteria are destroyed, fungi grow and cause infections. Many fungal infections appear in the upper layers of the skin while some penetrate to the deeper layers. Fungal spores when inhaled can lead to fungal infections that affect the whole body.

Other Infections

  • Protozoa, Helminths, and Ectoparasites are also responsible for causing infectious diseases. Protozoa are transferred by contact with faeces. Amoebic dysentery is caused by protozoa.
  • Helminths include flatworms and roundworms that cause infections in humans.
  • Ectoparasites such as mites, lice, ticks, etc. attach to the skin and cause infections.

Q.18. What are disease-causing agents?

Sol: Diseases are caused by different microorganisms including bacteria, fungi, viruses, protozoans, flies, worms, etc. These agents are called disease-causing agents.

Listed below are a few diseases and the disease-causing agents:

Disease Causative Agent
Plague Pasteurella pestis.
Cholera Vibrio comma (Vibrio cholera).
Tetanus Clostridium tetani.
Anthrax Bacillus anthracis.
Whooping cough Bordetella pertussis.
Human papillomavirus infection Human papillomavirus.
Chickenpox Varicella-zoster virus (VZV)
Meningoencephalitis Naegleria fowleri (amoeba)
Hepatitis Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, Hepatitis E viruses.
Acquired Immune Deficiency Syndrome (AIDS) Human Immunodeficiency Virus (HIV).

Q.19. List out the control measures and preventions for communicable diseases

Sol: A few precautions or control measures which should be carried to avoid infection and other spreading diseases are:

  1. Frequent washing our hands.
  2. Wear clean and ironed clothes.
  3. Maintain cleanliness around us.
  4. Drink only boiled and filtered water.
  5. Maintain proper hygiene in the food which we eat.
  6. Keep our body clean and tidy by having a regular bath.
  7. Disinfectants and other antiseptics can be used to destroy the microbes.
  8. Avoid the entry of vectors like mosquitoes, rats, house flies, cockroaches by spraying insecticides.

Q.20. What is Acquired Immunodeficiency Syndrome?

Sol: Acquired Immune Deficiency Syndrome – AIDS is a syndrome caused by the HIV virus. In this condition, a person’s immune system becomes too weak to fight off any kind of infection or disease. AIDS is usually the last stage of HIV infection, in which the patient’s body cells lack the energy to defend itself and thus spawns various diseases. AIDS, when untreated, leads to death.

Causes or Transmission of AIDS

AIDS can is transmitted only through specific activities including:

  • Having unprotected sex.
  • Transmission of infected blood.
  • Sharing infected sharp instruments like needles, blades, etc.
  • From a mother to her baby during pregnancy, parturition, and breastfeeding.

Structure of an HIV virus

Symptoms of AIDS

As AIDS is a virus infection, the symptoms related to acute HIV infection can be similar to flu or other viral illnesses, which includes:

  • Fever.
  • Chilis.
  • Weakness.
  • Diarrhoea.
  • Tiredness.
  • Headaches.
  • Sore throat.
  • Night Sweats.
  • Mouth sores.
  • Skin rashes.
  • Weight Loss.
  • Muscle & Joint Pain.
  • Swollen lymph glands.

Symptoms of late-stage HIV infection may include:

  • Dry cough.
  • Weight loss.
  • Night Sweats.
  • Blurred vision.
  • Shortness of breath.
  • Permanent tiredness.
  • Persistent or Chronic Diarrhea.
  • Swollen glands lasting for weeks.
  • White spots on the tongue or mouth.
  • Fever of above 37 degrees Centigrade (100 degrees Fahrenheit).

Treatments for AIDS

There are more than 25 drugs available and approved to treat HIV infected patients. These drugs are called antiretroviral drugs and are the combination of medications, which are collectively called the antiretroviral therapy, or ART.

We, at BYJU’S, aim to deliver students with all the necessary support and allow them to prove their abilities by excelling in their examination. Important Questions for RBSE Class 12 Biology Chapter-40, Important and Common Human Diseases are prepared under the guidance of RBSE syllabus for Class 12 with proper structure and after thorough research on the particular topics.

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