Why did the Maya use slash-and-burn farming techniques? to prevent soil erosion and water loss
to take advantage of the rich volcanic soil
to clear away the dense natural vegetation
to make use of the large sources of fresh water

After the success of the sputnik launch, the united states feared that they would never be able to launch their own satellite, the ussr had used technology developed by the united states, the soviets had superior nuclear capabilities, that any future us satellites would not be as successful.