Answer: They can affect the DNA of living things over time.
They occur in thousands of years or within billions of years.
They affect the populations and species more slowly then short term changes .
Explanation:
The long-term environmental changes are slow and gradual changes in the environment. This gives the population of the species the opportunity to adapt. These occur on Earth over thousands of years. The gradual changes affect the body form and function of living beings. The gradual changes can affect the instructional machinery like DNA synthesis and its function. Such changes develop unnoticeable and undetected symptoms in species. The fluctuation of climate in a region over thousand years can bring a catastrophic hazard like cyclone.