Which of the following is an example of a barter system

What are some examples of native americans were impacted by colonization in america

In a study, people were asked to imagine simple occasions that made them happy and to remember events that made them feel proud about themselves. it was observed that the subjects developed an increasingly positive attitude. these changes are known to be healthy, leading to greater physical activity and reducing unhealthy habits. based on this excerpt, we can conclude that a positive attitude .

Most galaxies in the universe are irregular-shaped galaxies. true or false ?