by Marlowe HOOD Agence France Presse PARIS, France (AFP) — As dozens of countries blocked the flow of people and goods from Britain to avoid a new and more contagious strain of coronavirus, scientists raced to understand how it emerged and the scope of its threat. Here are some of the key questions they are asking, and the answers that have emerged so far. – How often do viruses mutate? – All the time, but […]