Which of the following is a significant source of income for several native american groups in the united states? a. reservations tourism b. ranching c. farming d. casino gambling

The correct answer is - d. casino gambling.

In some parts of the United States, where once the land was of the Native Americans, there a lots of casinos built. Since this casinos are built on a land that was rightfully of the Native Americans, the casinos were obligated to pay the Native Americans, and in general this is performed in a way like paying a monthly or yearly wage in agreement between both sides about the sum that has to be paid. This type of income had made multiple Native American families to be able to live from this money without having to work anything else.  

the precambrian aged rocks could be found in australia. australia is a region that has a lot of ancient civilization history from million years ago. in this region, there are a lot of recognizable fossils buried in its land which is considered a precambrian-aged rocks