These parts are called gears. Gears are toothed mechanical components that transmit motion and power between rotating shafts. They are commonly used in machinery and vehicles to control speed, torque, and direction of rotation. Gears come in various shapes and sizes, each designed for specific applications. **

Rolex offers a range of accessories to complement their watches, including items such as watch winders, travel cases, and watch straps. These accessories are designed to enhance the experience of owning and using a Rolex watch, providing both practical and aesthetic benefits. Additionally, Rolex also offers a selection of branded merchandise such as pens, cufflinks, and keychains that allow enthusiasts to showcase their love for the brand. **

Bicycle spare parts are commonly referred to as bike components or bike parts. These include items such as tires, tubes, chains, pedals, brakes, gears, and handlebars. Having spare parts on hand can help ensure that a bike is well-maintained and can quickly be repaired if needed. **

The car parts in the image are called brake calipers. They are responsible for applying pressure to the brake pads, which then press against the brake rotors to slow down or stop the vehicle. The calipers house the pistons and are typically made of metal to withstand the heat and pressure generated during braking. They are an essential component of the braking system in a vehicle. **

The plumbing parts in the image are called pipe fittings. They are used to connect and control the flow of water or other fluids in a plumbing system. The specific fittings in the image include a T-joint, a 90-degree elbow, and a straight coupling. These fittings are essential for creating a secure and efficient plumbing system. **

The advent calendar with horse accessories is called the "Schleich Horse Club Advent Calendar." This calendar is designed for horse lovers and enthusiasts, featuring a variety of miniature horse figurines and accessories behind each door. It is a fun and interactive way to count down the days until Christmas while adding to a horse-themed collection. **

The main parts of a circle are the radius, diameter, circumference, and center. The radius is the distance from the center of the circle to any point on the circle. The diameter is a line segment that passes through the center of the circle and has endpoints on the circle. The circumference is the distance around the circle, while the center is the point within the circle that is equidistant from all points on the circle. **

The sun is composed of several layers, including the core, radiative zone, convective zone, photosphere, chromosphere, and corona. The core is the central region where nuclear fusion occurs, producing the sun's energy. Surrounding the core is the radiative zone, where energy is transported by photons. The convective zone is the outermost layer of the sun's interior, where hot plasma rises and cooler plasma sinks. The photosphere is the visible surface of the sun, while the chromosphere and corona are the outermost layers of the sun's atmosphere. **