Fill in the Blank Questions 44.________________ is defined as the percentage of the original population that survives to a given age. 45.Factors of weather and climate that operate on a population regardless of its size are called _____________________ effects. 46.The ________________ of a habitat is the number of individuals the habitat has the resources to support indefinitely. 47.The back-and-forth evolutionary adjustments species make to each other are examples of _________________. Â Â