A scientist culture the dried soup from a 4,000-year-old cooking pot found in an Egyptian tomb and obtain a distinctive species of prokaryote. You immerse a test tube of these bacteria in boiling water for several hours, but the colony grows back. This species is probablyA) endospore-forming.B) a spirochete.C) halophilic.D) a cyanobacteria.

Under conditions of starvation, especially the lack of carbon and nitrogen sources, a single endospore forms within some of bacteria, this process is called sporulation
The complete endospore consists of multiple layers of resistant coats (including a cortex, a spore coat, and sometimes an exosporium) surrounding a nucleoid, some ribosomes, RNA molecules, and enzymes
An endospore is not a reproductive structure but rather a resistant, dormant survival form of the organism
Endospores are quite resistant to high temperatures (including boiling), most disinfectants, low energy radiation, drying, etc
The endospore can then survive until a variety of environmental stimuli trigger germination, allowing outgrowth of a single vegetative bacterium
Small acid-soluble proteins saturate the endospore's DNA and protect it from heat, drying, chemicals, and radiation;they also function as a carbon and energy source for the development of a vegetative bacterium during germination
The cortex may osmotically remove water from the interior of the endospore and the dehydration that results is thought to be very important in the endospore's resistance to heat and radiation