Olympiad Test: Why do We Fall Ill- 1 - Class 9 MCQ

Common cold spreads through the mucus of the infected people through sneezing and coughing.

It is not spread among humans, but it is spread throughout the body by the cells. Leukemia is cancer of the white blood cells. Like other cancers it is not contagious.

AIDS (acquired immunodeficiency syndrome) is caused by the HIV virus. It breaks down the body immune system, leaving the patient vulnerable to a host of life-threatening opportunistic infections.

HIV (Human immunodeficiency virus)belongs to the special class of viruses called retrovirus within this class HIV is placed in a subgroup called lentivirus.

HIV consists of a viral envelope within the viral envelope 2 identical copies of single-stranded RNA are a present and reverse transcriptase enzyme.

Hence AIDS virus has single-stranded RNA.

The common cold virus is transmitted via airborne droplets (aerosols), direct contact with infected nasal secretions, or fomites (contaminated objects). The rest are generally sexually transmitted diseases.

Tuberculosis or TB is a disease that affects the human lungs. It has an infectious nature and this disease is highly communicable. Tuberculosis is spread by Mycobacterium Tuberculosis. This particular bacterium is spread by coughing and sneezing with the droplets released during these processes. Recurring and frequent cough, blood vomit, fever, fatigue, exhaustion, weakness, and other serious symptoms are part of this disease. It may also affect other organs depending on the severity.

Vector Borne diseases are the illness caused by the vectors. A vector is a carrier of the causative microbe for various diseases such as mosquitoes, ticks and fleas.A vector is any pathogen that carries and transmits any infectious agent into other living organisms. These vectors may be parasites or other microbes.The diseases spread by vectors are: Malaria, dengue, zika fever, yellow fever, rickettsial disease, Leishmaniasis, Trypanosomiasis, filariasis, etc.

Malaria is a mosquito-borne infectious disease caused by various species of the parasitic protozoan microorganisms called Plasmodium.

Congenital hemophilia is an inherited bleeding disorder characterized by an absent or reduced level of clotting factor VIII(8) or factor IX(9). In a person with a normal amount of clotting factor, when bleeding starts, all of the clotting factors work together to form a clot that stops the bleeding.

Typhoid fever is a bacterial infection caused by Salmonella typhi. Symptoms include gradual onset of high fever over several days, fever fluctuation is seen with bradycardia (slow pulse), abdominal pain and tenderness (inflammation), delirium (acute confusion state) is frequent, rose color spots appear on the lower chest and abdomen, weakness, headache. So, the correct answer is 'Typhoid'.

The vaccine contains weakened or killed microbe, its toxin, or one of its surface proteins. It provides the individual active acquired immunity. For example, if a child is given polio vaccine then that child will be immune to polio disease as it will activate the immune response and lead to the production of antibody and even the memory cells get prepared against the attack.