1) Typically in order to view a lot of endospores in a bacterial culture capable of forming such structures, one would allow the culture to grow for 4‐5 days (rather than 18‐24 hrs). Why would one have use such a prolonged growth interval for this purpose?

In older bacterial cultures, endospore formation is enhanced when all the nutrients within the culture media are exhausted.

Explanation:

Endospores are dormant bodies produced by the bacteria Bacillus, Clostridium, (these two contain deadly pathogens) and Sporosarcina.

Endospore formation is mainly triggered by the depletion of nutrients, especially amino acids. Once this stimulus has been received by the vegetative cell, it converts to a committed sporulating cell called a sporangium. Complete transformation of a vegetative cell into a sporangium and then into an endospore requires 6 to 12 hours in most spore-forming species.

Endospores can withstand harsh environmental conditions and this facilitates their survival.

Therefore, as the nutrients in the culture diminish, more endospores would be formed.

its probably to later but whats the question