Test 2

The early universe was too cool, and lithium, beryllium, and boron all have lower binding energies per nucleon. Big Bang nucleosynthesis could only produce trace amounts of Li, Be, and B because there were no stable nuclides with five or eight nucleons. Approximately 20 minutes after the Big Bang, the universe cooled, and the abundances of nuclides in the universe were fixed. By the time enough ⁴He had built up to form heavier elements, the universe was not hot enough for fusion reactions to occur, leaving stellar nucleosynthesis the only avenue to produce Li, Be, and B.