Hey there! I'm happy to help!
Within the biosphere, all of the Earth's other spheres work together.
The root word "bio" means life, and in biology, that is what we are studying! The biosphere encompasses the life in all parts of the Earth. The water (hydrosphere), the air (atmosphere and troposphere), and the ground (lithosphere). These are all driven by life, which is what they all have in common.
Have a wonderful day and keep on learning! :D