I guess you don’t technically need a nucleus, that’s what they proved here. But remember that gluons are what bind quarks together. And quarks are what actually make up a Proton or Neutron.

This is kinda away from the other replies to your comment. But I took that meme as saying plants get CO2 from the air (blue - scattering) and use sunlight (yellow - not really but meh) to produce many things with it, including chlorophyll which is the green pigment in plants.

Smooth surfaces such as polished metal have fewer areas to harbor bacteria compared to the fibers of a wooden door, for instance. In addition, a flat surface is easier to clean than a round knob.

Another benefit is that some metals have a natural antibacterial property toward bacteria organisms on their surfaces.