Assertion (A): A healthy lifestyle can reduce the risk of many
chronic diseases.
Reason (R): Healthy habits like balanced diet, regular
exercise, and avoiding smoking can improve immune function and reduce the risk
of disease.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Adopting a healthy lifestyle strengthens the
immune system, prevents obesity, and reduces the likelihood of chronic diseases
such as diabetes, heart disease, and cancer.
Assertion (A): The immunity provided by vaccines is an example
of acquired immunity.
Reason (R): Vaccines stimulate the production of antibodies in
the body by exposing it to an antigen in a safe form.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Vaccination introduces a harmless form of the
pathogen, stimulating the body to produce antibodies and memory cells for future
protection, which is a form of acquired immunity.
Assertion (A): HIV infection leads to AIDS.
Reason (R): HIV destroys helper T-cells, which are essential
for the functioning of the immune system, leading to immune system failure.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: HIV attacks helper T-cells, weakening the immune
system, which leads to acquired immune deficiency syndrome (AIDS).
Assertion (A): The most common form of cancer in women is
breast cancer.
Reason (R): The uncontrolled division of abnormal cells in the
breast tissues leads to the development of a tumor.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Breast cancer occurs due to mutations and abnormal
cell growth in the breast tissue, and it is one of the most common cancers in
women.
Assertion (A): Tuberculosis (TB) is a contagious disease.
Reason (R): TB bacteria are transmitted through the air when an
infected person coughs or sneezes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: TB is caused by Mycobacterium tuberculosis,
which spreads through respiratory droplets when an infected person coughs or
sneezes.
Assertion (A): Antibiotics are effective in treating viral
infections.
Reason (R): Antibiotics kill bacteria, not viruses.
Answer: (B) A is false, but R is true.
Explanation: Antibiotics are only effective against bacterial
infections and do not work against viral infections such as the common cold or
influenza.
Assertion (A): Malaria is caused by a protozoan parasite.
Reason (R): The Plasmodium parasite is transmitted to humans
through the bite of an infected female Anopheles mosquito.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Plasmodium is the protozoan responsible
for malaria, and it is transmitted to humans through the bite of an infected
Anopheles mosquito.
Assertion (A): Atherosclerosis is a condition that affects the
blood vessels.
Reason (R): It is caused by the buildup of plaque in the
arteries, which leads to restricted blood flow.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Atherosclerosis occurs when fatty deposits, or
plaque, accumulate on the artery walls, leading to a narrowing of the blood
vessels and reduced blood flow.
Assertion (A): Anemia is caused by a deficiency of red blood
cells.
Reason (R): Anemia results from inadequate iron levels, which
are essential for the production of hemoglobin in red blood cells.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Anemia is often due to iron deficiency, which
impairs hemoglobin production and results in reduced oxygen-carrying capacity of
the blood.
Assertion (A): Genetic disorders are inherited from parents.
Reason (R): Inherited genetic disorders are caused by mutations
in the DNA that can be passed from parent to offspring.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Genetic disorders like cystic fibrosis and sickle
cell anemia are passed from parents to children through inherited mutations in
the genes.
Assertion (A): Dengue fever is caused by a virus.
Reason (R): Dengue is transmitted through the bite of Aedes
mosquitoes that are infected with the dengue virus.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Dengue fever is caused by the dengue virus, which
is spread by Aedes mosquitoes.
Assertion (A): Cholera is caused by bacterial infection.
Reason (R): Cholera is caused by Vibrio cholerae,
which infects the small intestine and causes severe diarrhea.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Vibrio cholerae is the bacterium
responsible for cholera, leading to symptoms like severe diarrhea, dehydration,
and potentially death.
Assertion (A): The human immune system is capable of
recognizing and destroying foreign invaders.
Reason (R): The immune system has specific cells and antibodies
designed to target pathogens such as bacteria and viruses.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The immune system is equipped with cells (like
T-cells and B-cells) and antibodies that can specifically identify and destroy
foreign invaders.
Assertion (A): Polio is caused by a virus.
Reason (R): The polio virus primarily affects the nervous
system and can cause paralysis.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Polio is caused by the poliovirus, which can
damage the nervous system and lead to paralysis, especially in children.
Assertion (A): A balanced diet helps maintain good health.
Reason (R): A balanced diet provides essential nutrients
required for the body's growth, repair, and energy production.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: A balanced diet, containing the right amounts of
proteins, fats, carbohydrates, vitamins, and minerals, is necessary for
maintaining overall health.
Assertion (A): Hypertension is often referred to as the "silent
killer."
Reason (R): Hypertension can damage organs like the heart and
kidneys without showing immediate symptoms.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: High blood pressure can cause serious damage to
vital organs without noticeable symptoms, which is why it is called the "silent
killer."
Assertion (A): Alcohol consumption can weaken the immune
system.
Reason (R): Excessive alcohol reduces the production of white
blood cells, impairing the body's ability to fight infections.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Heavy alcohol consumption interferes with the
immune system’s function, making individuals more susceptible to infections.
Assertion (A): Cancer cells are characterized by uncontrolled
cell division.
Reason (R): Mutations in genes that regulate cell growth lead
to the formation of tumors.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Cancer occurs due to mutations in genes that
control cell growth, leading to uncontrolled division and the formation of
tumors.
Assertion (A): Malaria is caused by a protozoan parasite.
Reason (R): The Plasmodium parasite is transmitted by
the bite of an infected Anopheles mosquito.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Malaria is caused by Plasmodium parasites
transmitted by the bite of infected Anopheles mosquitoes.
Assertion (A): Autoimmune diseases occur when the immune system
attacks its own cells.
Reason (R): In autoimmune diseases, the immune system
mistakenly recognizes body cells as foreign and triggers an immune response
against them.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: In autoimmune diseases like rheumatoid arthritis
and lupus, the immune system mistakenly targets and damages the body’s own
tissues.
Assertion (A): Vaccines help in the prevention of several
infectious diseases.
Reason (R): Vaccines stimulate the body's immune system to
produce antibodies against specific pathogens without causing disease.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Vaccines trigger an immune response by introducing
a harmless form of the pathogen, providing immunity against future infections
from the pathogen.
Assertion (A): Vitamin D deficiency can lead to bone diseases.
Reason (R): Vitamin D is essential for calcium absorption in
the body, which is necessary for bone health.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Vitamin D helps the body absorb calcium, which is
crucial for strong bones. Its deficiency can lead to diseases like rickets or
osteomalacia.
Assertion (A): Antihistamines are commonly used to treat
allergic reactions.
Reason (R): Histamine is released during an allergic reaction
and causes symptoms like itching and swelling. Antihistamines block the action
of histamine.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Antihistamines work by blocking histamine
receptors, alleviating symptoms of allergic reactions such as itching, swelling,
and redness.
Assertion (A): Genetic predisposition plays a role in the
development of many diseases.
Reason (R): Some diseases, like heart disease and diabetes, are
influenced by inherited genetic factors.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Genetic factors can increase the likelihood of
certain diseases, such as heart disease and diabetes, but environmental factors
also play a significant role.
Assertion (A): Smoking is a major risk factor for lung cancer.
Reason (R): Tobacco smoke contains carcinogens that can damage
lung tissues and lead to cancer.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Smoking exposes the lungs to harmful chemicals,
including carcinogens, which can damage lung cells and lead to the development
of cancer.
Assertion (A): Viral infections cannot be treated with
antibiotics.
Reason (R): Antibiotics target bacterial infections, not viral
pathogens.
Answer: (B) A is true, but R is false.
Explanation: Antibiotics are designed to target bacteria and
are ineffective against viruses. Treatments for viral infections typically
involve antiviral medications or supportive care.
Assertion (A): Cancer is primarily caused by uncontrolled cell
division.
Reason (R): Cancer cells have mutations in genes that regulate
cell growth and division.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Cancer occurs due to mutations in the genes
responsible for regulating cell division, leading to uncontrolled growth and
formation of tumors.
Assertion (A): A deficiency in insulin causes diabetes
mellitus.
Reason (R): Insulin is a hormone produced by the pancreas that
helps regulate blood glucose levels.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Diabetes mellitus is caused by insufficient
production or improper functioning of insulin, which leads to elevated blood
sugar levels.
Assertion (A): Genetic counseling can help individuals assess
the risk of inherited genetic disorders.
Reason (R): Genetic counseling involves analyzing family
history and genetic tests to provide insights on possible hereditary conditions.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Genetic counseling helps families understand the
likelihood of inherited diseases and can guide decision-making on preventive or
therapeutic measures.
Assertion (A): The use of insecticide-treated bed nets helps
control the spread of malaria.
Reason (R): The Anopheles mosquito, which transmits the malaria
parasite, bites primarily during nighttime.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Bed nets treated with insecticides prevent
mosquito bites, thus reducing the risk of malaria transmission, especially since
the Anopheles mosquito is most active at night.
Assertion (A): Obesity increases the risk of developing
cardiovascular diseases.
Reason (R): Excess fat accumulation leads to the buildup of
plaque in blood vessels, increasing the risk of atherosclerosis.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Obesity contributes to the accumulation of fat and
cholesterol in blood vessels, which can lead to atherosclerosis, thereby
increasing the risk of heart disease and stroke.
Assertion (A): Exercise is beneficial in managing hypertension.
Reason (R): Regular physical activity helps lower blood
pressure by improving heart function and circulation.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Regular exercise strengthens the heart, reduces
blood vessel resistance, and helps lower blood pressure, which is beneficial for
managing hypertension.
Assertion (A): Antibodies are produced by B-cells during an
immune response.
Reason (R): B-cells differentiate into plasma cells, which
secrete antibodies to neutralize pathogens.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: During an immune response, B-cells mature into
plasma cells that produce antibodies specific to the antigen, which helps in
neutralizing or eliminating the pathogen.
Assertion (A): A healthy liver is essential for detoxification
in the body.
Reason (R): The liver processes toxins and metabolic waste
products, converting them into forms that can be safely eliminated.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The liver plays a vital role in detoxifying
harmful substances by breaking them down or converting them into less harmful
compounds that can be excreted by the body.
Assertion (A): Malaria can be prevented through the use of
antimalarial drugs.
Reason (R): Antimalarial drugs inhibit the growth of
Plasmodium parasites, preventing the disease.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Antimalarial drugs, such as chloroquine and
artemisinin-based combination therapies (ACTs), target Plasmodium
parasites and can be used for both treatment and prevention of malaria.
Assertion (A): Smoking is a major cause of lung cancer.
Reason (R): Tobacco smoke contains carcinogens that can damage
lung tissue and trigger mutations.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Carcinogenic chemicals in tobacco smoke can lead
to genetic mutations in lung cells, which increases the risk of lung cancer.
Assertion (A): Leprosy is caused by a bacterial infection.
Reason (R): Mycobacterium leprae causes leprosy,
affecting the skin and peripheral nerves.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Mycobacterium leprae is the bacterium
responsible for leprosy, a disease that affects the skin, nerves, and mucous
membranes, leading to deformities if left untreated.
Assertion (A): The primary function of the immune system is to
defend the body against infections.
Reason (R): The immune system uses a variety of cells and
molecules to identify and eliminate pathogens.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The immune system protects the body by identifying
and destroying pathogens such as bacteria, viruses, and fungi using specialized
cells like macrophages, T-cells, and B-cells.
Assertion (A): Antibiotic resistance is a growing problem in
healthcare.
Reason (R): Overuse and misuse of antibiotics have led to the
development of resistant bacterial strains.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Over-prescription and inappropriate use of
antibiotics contribute to the evolution of antibiotic-resistant bacteria, making
infections more difficult to treat.
Assertion (A): Cardiovascular diseases are the leading cause of
death worldwide.
Reason (R): Factors like high blood pressure, high cholesterol,
and smoking increase the risk of heart attacks and strokes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Risk factors such as hypertension, smoking, and
high cholesterol contribute to the development of cardiovascular diseases like
heart attacks and strokes, which are among the leading causes of death globally.
Assertion (A): High levels of cholesterol in the blood increase
the risk of atherosclerosis.
Reason (R): Cholesterol forms plaque in blood vessels,
restricting blood flow and increasing the likelihood of clots.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: High cholesterol leads to the accumulation of
plaque in the arteries, causing atherosclerosis, which increases the risk of
heart attack and stroke.
Assertion (A): Antibiotics are used to treat bacterial
infections.
Reason (R): Antibiotics can target specific components of
bacterial cells, killing or inhibiting their growth.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Antibiotics target specific structures or
functions in bacterial cells, such as cell wall synthesis or protein production,
making them effective in treating bacterial infections.
Assertion (A): Protein-energy malnutrition is a condition in
which a person suffers from inadequate protein and calorie intake.
Reason (R): This malnutrition leads to a reduction in body
weight, muscle mass, and immune function.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Protein-energy malnutrition, such as in
kwashiorkor and marasmus, results in insufficient intake of proteins and
calories, leading to severe health problems like weight loss, muscle wasting,
and immune dysfunction.
Assertion (A): Vaccines can help prevent infectious diseases by
stimulating the immune system.
Reason (R): Vaccines introduce a harmless part of the pathogen,
prompting the immune system to produce antibodies.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Vaccines work by exposing the body to a
non-virulent part of the pathogen, which stimulates the immune system to produce
antibodies and memory cells for future protection.
Assertion (A): Influenza is a viral infection that affects the
respiratory system.
Reason (R): The flu virus causes fever, body aches, and
respiratory distress, which are characteristic symptoms of influenza.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The influenza virus infects the respiratory tract,
causing symptoms like fever, cough, sore throat, and body aches.
Assertion (A): Malaria is caused by a protozoan parasite.
Reason (R): Plasmodium is the protozoan parasite
responsible for malaria, transmitted by Anopheles mosquitoes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Plasmodium is the parasite that causes
malaria, and it is transmitted to humans through the bites of infected Anopheles
mosquitoes.
Assertion (A): The body’s natural defense against infections
includes both specific and nonspecific immune responses.
Reason (R): The nonspecific immune response includes barriers
like the skin, while the specific immune response involves lymphocytes targeting
pathogens.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The immune system uses both nonspecific (like the
skin and phagocytes) and specific (like antibodies and T-cells) responses to
defend against pathogens.
Assertion (A): Obesity is a risk factor for type 2 diabetes.
Reason (R): Excessive body fat causes insulin resistance, which
disrupts normal glucose metabolism.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Obesity leads to insulin resistance, which impairs
glucose uptake by cells, resulting in high blood sugar levels and eventually
type 2 diabetes.
Assertion (A): Tuberculosis (TB) is an infectious disease
caused by bacteria.
Reason (R): Mycobacterium tuberculosis is the
bacterium that causes TB, primarily affecting the lungs.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Mycobacterium tuberculosis causes
tuberculosis, a respiratory disease that primarily affects the lungs but can
spread to other organs.
Assertion (A): Anemia can be caused by a deficiency of iron in
the diet.
Reason (R): Iron is essential for the production of hemoglobin,
which carries oxygen in the blood.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Iron is a key component of hemoglobin, and a
deficiency in iron reduces hemoglobin levels, leading to anemia.