An example of a secondary consumer is a

hawk (that eats a snake).
oak tree
panther (that eats a deer).
deer (that eats grass).

A panther because it eats the primary consumer which would be the deer.
an oak tree is the producer (bottom of the food chain)
the deer is the primary consumer because it eats grass which would also be a producer
and the hawk would be the top predator because it eats a snake which would eat a mouse which would feed on a producer :)

If the experiment was perfomed more then once and you get the same results