Since the article takes a long time to get to a simple point:
The three elements are lithium, beryllium, and boron. They cannot be formed from hydrogen and helium combinations (as carbon can) because the resulting isotopes are unstable. However, cosmic rays from "black holes, neutron stars, supernovae, and active galaxies" are very high energy and can split heavier elements into these three in a process called spallation.
Since the article takes a long time to get to a simple point:
The three elements are lithium, beryllium, and boron. They cannot be formed from hydrogen and helium combinations (as carbon can) because the resulting isotopes are unstable. However, cosmic rays from "black holes, neutron stars, supernovae, and active galaxies" are very high energy and can split heavier elements into these three in a process called spallation.