In my opinion Aerial photograph
Answer:
This is a primary source, namely a written one, because it derives directly from the past and its content hasn't been alternated.
Explanation:
Historians are dividing sources into primary and secondary. Primary sources are derived directly from the past, meaning that they are created at the time when some event happened. This is an example of primary source, as it is an original letter that one ruler sent to another one.
They can catch fire easily due to the materials that are used to make them
It’s is Australia and Russia