Which of the following is an example of a long-term change to ecosystems?

a.) seasons
b.) tide cycle
c.) evolution
d.) population growth

Evolution seems to be the best answer for this question.

Seasons on Earth tend to last only a few months (i.e. summer lasts from June to September).

Tide cycles are visible throughout a day.

Population growth tends to occur over the course of a few years, decades, or centuries. Decline can take place at the same rate.

Finally, evolution takes place over the course of hundreds of thousands or millions of years. When evolution occurs, organisms often require different resources to survive. This has the power to change the face of an ecosystem for hundreds of thousands of years.

The correct answer is a. we know this because n (hap) + n (hap) = 2n (dip).