What is the difference between natural systems and human systems?

Soweto was the site of one of the that swept across south africa in the late 1970s. in his effort to end apartheid, desmond tutu turned to . the united states responded to south africa’s apartheid policy in the 1980s by .

Based on what you know about the location of the earth in relation to the sun, why is this called the goldilocks zone in other galaxies?

There are 4 red balls, 6 white balls, and 3 green balls in a bag. if one ball is drawn from the bag at random, what is the probability that it is not white?