Answer:
Primary source
Step-by-step explanation:
A photograph showing the construction of the Panama Canal is a primary source.
A primary source is an original document or artifact that was created by someone who was directly involved in the event or phenomenon that you are studying.
A photograph of the construction of the Panama Canal was created by someone who was there and witnessed the event. Therefore, it is a primary source.
A secondary source is an interpretation of an event or phenomenon that was created by someone who was not directly involved. For example, a book about the construction of the Panama Canal would be a secondary source

Here are some other examples of primary sources:
- Letters
- Diaries
- Newspaper articles
- Maps
- Photographs
Here are some other examples of secondary sources:
- Books
- Articles
- Movies
- Documentaries
- Websites