I think the most critical consequence of the advancement of the amniotic egg it the tetrapods were no longer attached to the water for reproduction.The amniotic egg permits reptiles, flying creatures, and warm-blooded creatures to lay eggs ashore without drying out. The liquid filled depression containing the incipient organism is isolated from the outer condition by an amniotic sac that is impermeable to water.
South African people are vaccinated with Yellow fever. First, SA is strict in the implementation proof of vaccination in travelers coming in the country. The vaccination card must show vaccination at least ten days prior to travel. This is to prevent reintroduction of the disease to SA people. Second, In the list of Center for Disease Control, South Africa is not included in the countries with an endemic Yellow fever which means that the disease is wiped out if not controlled through vaccination.
To protect it from the acids
