When were the heat-trapping effects of gases that cause the greenhouse effect first measured by scientists?

Answer the questions in the image for zoom in to see better

Which of the following is not true of the xiongnu empire? burial mounds included glass beads and mirrors made from the sands throughout the region. there was more cooperation through trade between the tribes. other tribal units that were eventually assimilated were indo aryan, xianbei, hunyu, scythina and han chinese. as each nomadic tribe and civilization was conquered or absorbed into the larger empire, the xiongnu were able to hold more territory.

Write two letters to the editor describing a specific event from the cold war, such as the korean war or the vietnarm war. imagine you are writing the letters from the perspectivees of two world leaders who are on different sides of the conflict. each letters should explain the specific point of view of that person and use historical evidence to support any cliams.