Step 1: Understanding the Concept:
The question asks to identify the historical figure credited with the first observation of microorganisms.
Step 2: Detailed Explanation:
Let's look at the contributions of each scientist:
\[\begin{array}{rl} \bullet & \text{1. Antonie van Leeuwenhoek (1632-1723): A Dutch cloth merchant, he is known as the "Father of Microbiology." He crafted high-quality single-lens microscopes and was the first person to observe and meticulously describe single-celled organisms, which he called "animalcules" (now known as microorganisms), from samples like pond water and tooth scrapings. } \\ \bullet & \text{2. Zaccharias Janssen (c. 1585-1632): He was a Dutch spectacle-maker who is often credited, along with his father Hans, with inventing the first compound microscope around 1590. However, he is not known for using it to observe microorganisms. } \\ \bullet & \text{3. Robert Hooke (1635-1703): An English scientist who, in his book *Micrographia* (1665), coined the term "cell" after observing the structure of cork under a compound microscope. He observed the cell walls of dead plant cells, not living microorganisms. } \\ \bullet & \text{4. Robert Brown (1773-1858): A Scottish botanist who discovered and named the cell nucleus in orchids in 1831. He also described Brownian motion. } \\ \end{array}\]
Therefore, Antonie van Leeuwenhoek was the first to see and describe living microorganisms.
Step 3: Final Answer:
Antonie van Leeuwenhoek was the microbiologist who first used a simple microscope to see tiny living organisms in pond water.
Arrange the following needs in the order in which they appear in the Maslow's Hierarchy of Needs, starting from bottom to top.
(A) Social
(B) Physiological
(C) Esteem
(D) Safety