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.
Technically, a recursive function is a function that makes a call to itself. To prevent infinite recursion, you need an if-else statement (of some sort) where one branch makes a recursive call, and the other branch does not.