Endospores are hardy, defensive structures that enable some bacteria to survive harmful environmental conditions, such as starvation, high temperatures, desiccation (drying out), chemical disinfectants and extremes in pH.
Recursive formula is a formula that is used to determine the next term of a sequence using one or more of the preceding terms.
Point being, you must include the starting number in any recursive definition. 1  1) An initial condition that tells where the sequence starts.  2) A recursion formula that tells how any term of the sequence relates to the preceding term.