The correct answer to the question "Which correctly describes Earth's population over the centuries?" is:
D. It has risen steadily.
1. Earth's population has not remained steady overall or declined in some places due to migration. Instead, it has consistently increased over the centuries.
2. This growth is attributed to various factors such as advancements in healthcare, technology, agriculture, and sanitation.
3. As a result of these advancements, people are living longer, infant mortality rates have decreased, and food production has become more efficient.
4. The steady rise in Earth's population is a significant global trend that has implications for resource management, urbanization, and environmental sustainability.
Therefore, the most accurate description of Earth's population over the centuries is that it has risen steadily.
