The correct answer is D. biosphere.
The biosphere is the part of Earth where life exists. It includes the land, water, and air, and all the organisms that live in these areas. The biosphere is a dynamic system, with living things constantly interacting with each other and with their environment.
The lithosphere is the solid outer layer of Earth. It includes the crust and the upper mantle. The lithosphere is divided into tectonic plates, which move slowly over time.
The hydrosphere is the water on Earth. It includes the oceans, lakes, rivers, and glaciers. The hydrosphere is essential for life, as it provides water for drinking, irrigation, and other uses.
The atmosphere is the layer of gases that surrounds Earth. It protects life from harmful radiation and helps to regulate the Earth’s temperature.
The biosphere is the most important part of Earth, as it is the only place where life exists. The biosphere is a delicate system, and it is important to protect it from damage.