Final answer:
True, lithium was produced during the Big Bang as one of the lightest elements alongside hydrogen and helium, which constituted the majority of the early universe's matter.
Step-by-step explanation:
The statement that Robert V. Wagoner discovered that the element with the symbol Li (lithium) is produced in the universal fireball is True. Lithium, which is the third element in the periodic table, was indeed produced during the Big Bang, the massive explosion that is theorized to have created the universe. As the universe expanded and cooled during the first few minutes of its existence, light nuclei formed, including hydrogen, helium, and small quantities of deuterium, helium-3, and lithium. The majority of the universe's mass became hydrogen (75%) and helium (25%), with deuterium and helium-3 accounting only for tiny fractions and lithium even less. However, it is important to note that heavier elements like carbon and oxygen had to be formed later through the process of stellar nucleosynthesis, as they were not products of the Big Bang itself.