It is called a joint. Joints are also called articulations, they are strong connections that join the bones, teeth, and cartilage of the body to one another. Each joint is specialized in its shape and structural components to control the range of motion between the parts that it connects. Joint is usually formed of fibrous connective tissue and cartilage, they may be grouped according to the type of motion: ball and socket joint, hinge joint, condyloid joint, which permits all forms of angular movement except axial rotation, pivot joint, gliding joint, or saddle joint.
Fusion and gravity
Fusion and gravity keep the sun from blowing itself up. A large amount of energy is released by the
sun. Protons are fused together to form helium atoms due to the high heat and
pressure at the center of the sun. The Sun does not blow itself up from the
outer pressure of nuclear fusion in as much as the inner force of gravity
balances it.
Osmosis is the movement of water particles from an area of high concentration of water particles to an area of low concentration of water particles across a semi permeable membrane
Diffusion is the movement of particles from an area of high concentration of particles to an area of low concentration of particles across a partially permeable membrane
Plasmolysis is the shrinking of the cytoplasm if a plant cell in response to diffusion of water out of the cell and into a high salt concentration solution as the cell membrane would pull away from the cell wall
Hope this helped