Explanation

Eduard Zirm performed the world's first successful human cornea transplant in 1905.

The operation restored vision to a man who had been blinded by a chemical burn.

Explanation

Ole Rømer, an astronomer from Denmark made the first quantitative measurements of the speed of light in 1676.

Explanation

Samuel Hahnemann (1755–1843), a German physician, formulated the principles of homeopathy in the late 18th century.

He introduced the concept of "like cures like" (similia similibus curentur).

He published "Organon of the Healing Art" (1810).

Explanation

dielectric, insulating material, or a very poor conductor of electric current. 

When dielectrics are placed in an electric field, practically no current flows in them because, unlike metals

Explanation

Alexei Leonov was the first human being to walk in space,

the man who would have been first on the moon had the Soviets beaten the Americans.

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First man who travelled in Space was Yuri Gagarin in 1961

First man who Walk in Space was Alexei Leonov in 1965

First man who Walk on Moon was Neil Armstrong in 1969

Explanation

Joseph Priestley discovered laughing gas (nitrous oxide) in 1772.

It was later studied for its anesthetic properties.

Explanation

Omer-Khayam was born in Iran in 1048 AD.

Omer-Khayam was a poet, Mathematician & Astronomer. 

Omer-Khayam introduced modern Solar Hijri calendar, the Jalali calendar.

Omer-Khayam  was the first to develop the binomial theorem and determine binomial coefficients.

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Explanation

John McCarthy is recognized as the father of Artificial Intelligence due to his astounding contribution in the field of Computer Science.

John McCarthy was an American computer scientist

Note: Artificial Intelligence is a branch of Computer science, which aims to create intelligent machines so that machine can think intelligently in the same manner as a human does.

Explanation

Robert Hook described the cell as: Basic unit of life

Robert Hook  discovered cells: 1665

Cell is the smallest unit that can live on its own and that makes up all living organisms and the tissues of the body

Explanation

Antonie van Leeuwenhoek is credited with the discovery of bacteria.

In 1676, using a primitive microscope, he observed and described microorganisms.

Including bacteria and protozoa, which he referred to as "animalcules".