Final answer:
Spores, or endospores, are more resistant to heat than vegetative bacterial cells. They form in response to environmental stress and can survive extreme conditions, including high temperatures that would kill vegetative cells.
Step-by-step explanation:
The form of a bacterial cell that is more resistant to heat is the spore, specifically an endospore. Bacterial endospores are extremely robust structures that protect the genetic material of the bacterium when conditions are unfavorable. They are formed through a process called sporulation, which begins in a vegetative cell when the environment becomes stressful, such as during nutrient depletion or exposure to extreme temperatures. An endospore can withstand harsh conditions including high temperatures, chemicals, and radiation, making it much more resistant than a vegetative cell. For instance, the genera Bacillus and Clostridium are known for their endospore-forming capabilities, helping them survive in hostile environments that would otherwise kill the vegetative cells.