Quarks are elementary particles and are considered to be the fundamental building blocks of matter. They are not composed of smaller particles. Quarks come in six different types, or flavors, known as up (u), down (d), charm (c), strange (s), top (t), and bottom (b).
Regarding the size of quarks, it is important to note that the concept of "size" in the context of elementary particles is not straightforward. Quarks are point-like particles, meaning they are considered to be dimensionless and do not have a measurable size in the traditional sense. However, they do possess certain properties such as mass, electric charge, and spin.
The up and down quarks (u and d) are the lightest and most common types of quarks found in ordinary matter, while the charm, strange, top, and bottom quarks are much heavier and are typically found in high-energy environments such as particle accelerators or the early universe.