Introduction:

The fundamental theory underlying the structural unit of life is known as cell theory. The cell theory is able to explain the structural unit, which is common in all the living organisms. The microscope development led to decoding the mystery about the fundamental unit and it confirmed that all the organisms are made up of cells. Anton van Leeuwenhoek was the first scientist to observe and describe the diversity of cells, such as blood cells, microscopic nematodes, and sperm cells.

Correct answer:

Anton van Leeuwenhoek invented more powerful microscope and was the first to describe the diversity of cells. The efficient use of advanced magnification techniques, Anton van Leeuwenhoek observed the different type of cells.

Explanation/Justification for the correct answer:

Option (d) is given as invention of the powerful microscope helped in describing the diversity of the cells. Anton van Leeuwenhoek was the first scientist who observes and describes the diversity of cells, such as blood cells, microscopic nematodes, and sperm cells. The magnifying power of microscopes was modified which resulted in the development of more powerful microscopes. Anton van Leeuwenhoek modified the magnifying power of microscopes, resulting in the invention of more powerful microscopes with magnification up to 300×. He was the first to observe the single-celled organisms and called them “animalcules”. Hence, Option (d) is correct.

Explanation for incorrect answers:

Option (a) is given as organisms made up of cells as an articulation. The claim was not just given by this scientist, rather a collective effort of scientists revealed that cells are the basic unit of all organism. So, it is a wrong answer.

Option (b) is given as the articulation that all cells have come from preexisting cells. This hypothesis was proposed by German scientist Rudolph Virchow. So, it is a wrong answer.

Option (c) is given as he invented the first microscope and observed by first cell Anton Van Leeuwenhoek. The first cell was observed by scientist Robert Hooke. So, it is a wrong answer.

In 1839, Schleiden & Schwann formally articulated that all organisms are composed of cells. A German scientist named Rudolph Virchow proposed that all cells arise from cells already in existence. Robert Hooke invented a microscope to examine the structure of cork from an oak tree. Leeuwenhoek further develop more powerful microscopes with magnification up to 300 ×; “×” refers to magnification power. Hence, the options (a), (b) and (c) are incorrect.