Final answer:
High heat kills microbes by denaturing proteins, destroying membrane integrity, and oxidizing cell components; thus, all the provided mechanisms contribute to microbial death caused by high heat.
Step-by-step explanation:
High heat can kill microbes by three primary mechanisms that disrupt their cellular integrity and inhibit vital biochemical processes. Firstly, it denatures proteins, which are crucial for cell structure and function, causing them to lose their three-dimensional structure and rendering them nonfunctional. Secondly, high heat can destroy the integrity of cellular membranes, leading to loss of essential cellular contents and an inability to regulate the passage of substances into and out of the cell.
Lastly, heat can also oxidize components of the cell, which means it can cause components to chemically react with oxygen, leading to damage or alterations that can be fatal to the microbe. Therefore, the correct answer to how high heat kills a microbe is: 'all of the available answers'.