1)Why would sending only a small group of people to settle Mars be considered a bad idea for the future of the population ? 2)Why did it take so long for the Americas to finally be successfully colonized ?

Imagine a rocket launching from earth and travelling to the moon. in which order would the rocket pass through the layers of the atmosphere? thermosphere, mesosphere, stratosphere, troposphere troposphere, mesosphere, stratosphere, troposphere thermosphere, stratosphere, mesosphere, troposphere troposphere, stratosphere, mesosphere, thermosphere