There are 4 essay questions. Please be sure to complete all of them with thorough substantive responses. Citations are required for all responses.1. Provide an example of an organism within each of the four main nutritional categories of microbes and describe how each obtains its essential nutrients.2. Provide evidence in support of or refuting the following statement: Microbial life can exist in the complete absence of both sunlight or organic nutrients.3. Polymerase chain reaction (PCR) is a technology that requires high temperatures to reproduce DNA fragments. Explain why the discovery of thermophilic archaea and their associated DNA polymerases was critical to the success of this technique.4. Summarize how the electron transport chain functions to produce ATP in a bacterial cell versus eukaryotic cell. Explain whether or not the term chemiosmosis accurately illustrates this process.