After the Soviets successfully detonated an atomic bomb in 1949, President Harry S. Truman ordered the creation of a hydrogen bomb project. With the help of the Polish mathematician Stanislaw Ulam, Dr. Teller developed a model for the hydrogen bomb known as the Teller-Ulam design
Not 100% sure but it might be operetta
It might be said that the French explorers learnt how to make boats suitable for the coastal waters, rivers and lakes when they were at the great Lakes. They decided to build small sailing- ships to travel the entire length of the Missouri and the Mississippi River to New Orleans on the golf of Mexico. They built native birch-bark canoes and large rafts.
Arab merchants brought news of their religion as they traded in different areas. There was a cultural exchange and due to international trade, Islam spread to other parts of the world.
B. Helen lived a very isolated life, surrounded only by family and a couple of friends.
