Answer:
Dr. Salk had to convince government officials to allow him to test the vaccine.
Step-by-step explanation:
Jonas Edward Salk was a North American physician, virologist and epidemiologist, better known as the inventor of the first anti-polio vaccine.
Salk needed to prove that his vaccine was effective against apoliomelitis, which was a devastating and terrible disease. To test the effectiveness of the vaccine, Salk needed government permission and so had to repeatedly ask government officials to allow him to continue his research and test the vaccines.