Question Discussion & Solution

All are creator except Publisher.

The correct answer is Calcium Carbonate.

Key Points

• The chief component of the nacre that constitutes the pearl is aragonite (CaCO₃).
• Nacre also contains a small amount of conchiolin, a hornlike organic substance (albuminoid) that is the main constituent of the mollusc's outer shell.
• Pearl also contains Magnesium Carbonate(MgCO₃) along with Calcium Carbonate.

Additional Information

• Calcium carbonate is a common substance found in rocks as the minerals calcite and aragonite and is the main component of eggshells, snail shells, seashells, and pearls. 
• The Molar Mass of Calcium Carbonate is 100.0869 g/mol.
• Melting point: 825 °C.

The correct answer is Cancer.

Concept: 

Infectious diseases:

• Infectious disease are diseases caused by bacteria, fungi, viruses, or parasites.
• Infectious diseases are transmitted by infectious agents.
• Infectious disease is spread by humans, plants, and insects. 
• Agents that spread pathogens or pass them on are known as vectors or disease intermediaries.

Explanation:

• Cancer is not an infectious disease. 
• Cancer cannot be passed from one person to another by breathing the same air, sharing a toothbrush, touching.
• Cancer is a disorder in which cell growth is uncontrolled.
• Changes in genes that control how our cells function, particularly how they grow and divide, cause cancer.
• Accelerating cell division rates or inhibiting normal control can result in gene mutations. 
• Cancer is sometimes caused by the genes we inherit from our parents.
• Cancer's Causes
  • Carcinogens such as tobacco, chemicals, alcohol, and ultraviolet radiation from the sun are among the leading causes of cancer.

Additional Information

• Cholera:
  • Cholera is a severe diarrheal infectious disease caused by Vibrio cholerae bacteria.
  • People who consume cholera-contaminated food or water may become ill.
  • The infection is frequently mild or without symptoms, but it can also be severe and life-threatening.
  • The disease's deadly effects are caused by a toxin produced by bacteria in the small intestine.
• TB (Tuberculosis):
  • Tuberculosis (TB) is an infectious disease caused by a Mycobacterium tuberculosis bacteria.
  • It was transmitted from person to person via microscopic droplets released into the air.
  • Usually bacteria attack the lungs, but tuberculosis bacteria can attack any part of the body, including the brain, kidney, and spine.
• Conjunctivitis: 
  • Conjunctivitis or pink eye is a viral disease that is caused by allergies or bacterial or viral infection.
  • It is the Inflammation or infection of the eyeball's outer membrane and the inner eyelid.
  • Conjunctivitis is highly contagious and is spread through contact with infected people's eye secretions

Given: Sportspersons, Shooters, Swimmers

Logic: All shooters and swimmers are sportspersons but shooters and swimmers have no common relation.

Hence, option (2) is the correct answer.

In this question we shows that Pen is used for Writing.

Similarly, Spoon is used for Eating.

But Gun comes under Weapon, Teacher teach in School and Eraser and Pencil is different things.

Option 1, 3 and 4 is not correct.

Hence, "Spoon : Eating" is the correct answer.