Answer:
They occur in thousands of years or within billions of years
They affect populations and species more slowly than short-term changes
They can affect the DNA of living things over time.
Explanation:
Environmental changes occur when natural phenomenon and activities if humans brings about a disturbance of the natural environment thereby causing a change or impact on the ecosystem of the environment. Environmental changes could be short-term or long-term. Short-term changes occur within minutes, days, weeks or more, and usually has a drastic impact on a population. Short-term change often do not allow organism in an environment to adapt well, and could lead to migrration or extinction of such species of organisms.
Long-term environmental change, on the other hand takes thousands or more years to occur. They occur gradually that their impact on organisms is barely noticeable. It gives enough time for the species of organisms in the environment to adapt. It could bring about a change in the DNA of organisms over time. An example of long-term environmental change is global warming resulting from climate change.
Therefore, the statements that describe long-term environmental changes are:
They occur in thousands of years or within billions of years
They affect populations and species more slowly than short-term changes
They can affect the DNA of living things over time.