Explanation

• Scientist: Edward Jenner
  • Discovery Year: 1796
  • Vaccine Type: Smallpox
  • Significance: First ever successful preventive vaccine
  • Extra Fact: Smallpox was declared eradicated in 1980 by WHO

Additional information:

• Edward Jenner is often called the “Father of Immunology.”

Last verified on 16-01-2026

Explanation

Colour of the plants is green due to the presence of Chlorophyll۔

Chlorophyll absorbs certain wavelengths of light within the visible light spectrum.

Chlorophyll is the green color pigment which absorbs wavelength from sunlight.

Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis. 

Explanation

The neutron is a neutral particle,

which is stable only in the confines of the nucleus of the atom.

Explanation

When the soap is in the form of micelles then it has the ability to clean the oily dirt which gets accumulated at the centre.

These micelles remain as colloidal solutions.

Therefore, the dirt from the cloth is easily washed away.

Explanation

In the early 1950s, the first successful vaccine was created by US physician Jonas Salk.

Salk tested his experimental killed-virus vaccine on himself and his family in 1953

First used Salk vaccine in 1955 ( in activated)

while 

A live attenuated (weakened) oral polio vaccine developed by Dr. Albert Sabin and first used in 1961.

Israel launched a polio vaccine drive after 1988 in April 2022.

Explanation

Explanation

For water, the boiling point is 100ºC at a pressure of 1 atm

The boiling point of water decreases at higher altitudes due to Low atmospheric pressure

The boiling point of water increases with increased atmospheric pressure

The boiling point of water decreases with decreased atmospheric pressure

ND17-1-2023

Explanation

Explanation

At the highest point of its trajectory, an object thrown upwards has a vertical acceleration due to gravity,

Which is approximately 9.8 m/s² downwards.

While the object's vertical velocity is momentarily zero at the highest point,

The acceleration due to gravity continues to act on it. 

**

RY12-02-23

Explanation

Light travels at about 300,000 kilometers per second in a vacuum with a refractive index of 1.0,

but slows down to 225,000 kilometers per second in water

and 200,000 kilometers per second in the glass.

ND16-3-2023