Johann grouped together Earth, Wind, and Fire as the first three elements.
The three types of spatial distribution are uniform distribution (evenly spaced), random distribution (no pattern), and clustered distribution (grouped together).
When three notes grouped together are played in the time of two notes of the same value, they are called a triplet. Triplets create a rhythmic division that allows for the equal subdivision of a beat into three parts, which adds a distinctive feel to the music. This term is commonly used in various musical genres to enrich the rhythmic texture.
Dmitri Mendeleev
Paraguay, Argentina and Brazil
This is because in Western cultures, numbers above a thousand are grouped in 3s; the Greek prefices for the SI system are also grouped in powers of 10^3.
Electrons, protons, and neutrons are grouped together because they are the three fundamental subatomic particles that make up an atom. Protons and neutrons are located in the nucleus of an atom, while electrons orbit around the nucleus. Together, these particles determine the chemical and physical properties of an element.
Archae, Bacteria and Eukaryota
Italy and Japan. Together, the three countries were called the Axis.
If your car has EIS ignition ( distributorless) and it is a 6 cylinder, then you have three separate coil packs. They are all grouped together, however, they can be replaced individually. Each coil pack fires two cylinders.
Newland, Moseley, , Dobereiner, Mendeleeff...
Commutativity.