After setting up a PCR reaction Phil noticed that he'd forgotten to put primers into the mix. When he runs a gel of the PCR reaction after the reaction is finished he sees a positive result. Is this result expected

This is an unexpected result. Absence of primers means that DNA polymerase cannot bind with the template DNA and allow its amplification. If Phil sees a positive band, it should be because of contamination of primers (same set of primer or other) with DNTPs, water, MgCl2, or PCR buffer. This is the reason that a negative run for PCR is always recommended.

The correct answer will be 1809.

Explanation:

Jean-Baptiste Lamarck or Lamarck is best known for his theory of evolution called "Theory of Inheritance of Acquired Characteristics" which proposed a mechanism of change of species on the basis of use and disuse of organs.

Lamarck published series of books on paleontology and invertebrate zoology but his book Philosophie zoologique which was published in 1809 clearly stated his theories of evolution.

Thus, 1809 is the correct answer.