Question

why do slime moulds and bacteria form spores under unfavorable conditions ?

Answer 1

When conditions become unfavorable, these slime molds form sporangia - clusters of spores. Spores from the sporangia are dispersed to new habitats, germinate into small amoebae, and the life cycle begins again.

Similarities in the life cycle of certain bacteria (the myxobacteria) and even an unusual ciliate have very similar life cycles, aggregating to form spores on a sporangium.