Which program studies how air, land, water, and life interact on earth?

The Earth Observatory System is the correct answer because it focuses specifically on the interactions between different components of the Earth's system, including the atmosphere (air), hydrosphere (water), lithosphere (land), and biosphere (life). This program utilizes satellites and ground-based observations to monitor and analyze environmental changes, natural phenomena, and human impacts on these interconnected systems.

Understanding how air, land, water, and life interact is crucial for addressing issues such as climate change, natural resource management, and ecosystem health. The Earth Observatory System provides valuable data and insights necessary for scientists, policymakers, and the general public to make informed decisions regarding environmental conservation and sustainable practices.

In contrast, the other options refer to different projects or historical exploration efforts that do not specifically encompass the comprehensive study of Earth's systems and their interactions.