Final answer:
Environmental stochasticity refers to random variations in birth and death rates occurring in populations from year to year. Hence, the statement is a) true.
Step-by-step explanation:
Environmental stochasticity refers to random variations in birth and death rates occurring in populations from year to year. These variations can be influenced by factors such as fluctuations in the environment, including rainfall and food sources, which can affect the availability of resources for the population.
Additionally, small isolated populations are particularly vulnerable to catastrophic events, such as floods or wildfires, which can have significant impacts on birth and death rates. The study of these demographic parameters and their fluctuations is an important aspect of population ecology and can help us understand population dynamics.