Which of following is a pair of viral diseases?

The correct answer is Common cold, AIDS.

Concept:

• The organisms which cannot be seen through the naked eyes are called microorganisms.
• Microorganisms are classified into four major groups. These groups are bacteria, fungi, protozoa and some algae.
• Viruses are also microscopic.
• Microorganisms are both beneficial as well as harmful.

Explanation:

• Microorganisms are harmful in many ways. Some of the microorganisms cause diseases in human beings, plants and animals.
• Such disease-causing microorganisms are called pathogens.
• On the basis of these pathogens, diseases can be categorised as - Viral diseases, Bacterial diseases, Nematode diseases, etc.
• Some of the viral diseases include - Measles, Chickenpox, Polio, Common cold, AIDS, etc.

Common Cold -

• The common cold can be caused by various types of virus-like the rhinovirus & coronavirus.
• Its symptoms include Runny nose, sneezing and congestion.

AIDS - 

• AIDS is the disease caused by HIV (human immune deficiency virus), first reported in the U.S.A in 1981.
• HIV belongs to the group of viruses called a retrovirus, these are named so because they(have RNA genome) have reverse transcriptase enzyme which carries on the process RNA →DNA 
• It destroys the defence mechanism of the body such that the person is unable to produce an immune response even against common bacteria like Mycobacterium, parasites like Toxoplasma, viruses, and fungi.

Additional Information 

Some Common Human Diseases are caused by Microorganisms.