Final answer:
The scientist who discovered heat-resistant bacterial spores is not listed among the options but Ferdinand Cohn is noted for his study on bacterial endospores. Making significant advances in microbiology, Louis Pasteur and Robert Koch's work led to improved understandings of microorganisms and disease causation.
Step-by-step explanation:
The scientist who discovered heat-resistant bacterial spores is not explicitly mentioned among the options provided. However, during the late 19th century, the landmark work by scientists like Louis Pasteur and Robert Koch laid the foundations for our understanding of microorganisms and their role in disease. Pasteur is renowned for his work in disproving spontaneous generation, developing the process of pasteurization, and creating vaccines. Koch developed methods for isolating bacteria and identified specific bacteria responsible for diseases such as anthrax, cholera, and tuberculosis. In this domain of study, Ferdinand Cohn is recognized as one who made significant contributions to bacteriology, including the discovery of the endospore, which is a heat-resistant form of bacteria. Neither Joseph Lister, known for antiseptic surgery techniques, nor Antonie van Leeuwenhoek, who first observed microorganisms, is directly credited with this discovery. Ignaz Semmelweis is remembered for advocating handwashing to prevent the spread of puerperal fever. Thus, while Ferdinand Cohn's name is not among the options, his contributions are closely related to the discovery of heat-resistant spores