The life-bearing layer on the Earth is the Biosphere.

Definition of Biosphere:
The Biosphere is the part of the Earth where living organisms exist. It includes all living things - plants, animals, and microorganisms - as well as the non-living components that support them, such as soil, air, and water.

Components of the Biosphere:
The Biosphere is composed of three major components:

1. Lithosphere: This is the solid, outermost layer of the Earth. It includes the soil, rocks, and minerals that make up the Earth's crust. The Lithosphere provides a habitat for many plants and animals, and it plays a crucial role in the cycling of nutrients and the regulation of the Earth's climate.

2. Hydrosphere: This is the Earth's water system, including oceans, rivers, lakes, and groundwater. The Hydrosphere supports a vast array of aquatic life, and it also plays a critical role in regulating the Earth's climate and weather patterns.

3. Atmosphere: This is the layer of gases that surrounds the Earth, extending from the surface up to about 10,000 km (6,200 miles). The Atmosphere is composed mainly of nitrogen, oxygen, and trace amounts of other gases. It provides the air we breathe and protects us from harmful radiation from the sun.

Importance of the Biosphere:
The Biosphere is essential for the survival of all living things on Earth. It provides us with food, water, and other resources, and it also plays a critical role in regulating the Earth's climate and weather patterns. However, the Biosphere is under threat from human activities such as deforestation, pollution, and climate change. It is therefore essential that we take steps to protect and preserve the Biosphere for future generations.