Question

excerpt from tools of the spymaster
which statement best expresses the central idea of the excerpt?
james jay was a spy for the americans and had
knowledge of chemistry.
james jays system required two chemicals for
writing and reading invisible ink messages.
james jay believed secret messages that became
visible because of heat were not secure.
james jays invisible ink system allowed
washington to read secret messages

Explanation:

The text describes Jay's invisible ink system which needed two chemicals - one to write (invisible) and another to make it visible. This shows the system required two chemicals for writing and reading.

Answer:

James Jay’s system required two chemicals for writing and reading invisible ink messages.