The correct cause and effect relationship for the sentence given above is ONE CAUSE AND ONE EFFECT.
For the sentence given in the question, the cause is that the speaker forgot his keys and the effect was that he could not enter into his house. A cause can result into an effect and at other times, a single cause can result into multiple effects.
When it comes to examining the concepts of ethos, logos and pathos, I thought it best to look at these concepts being done well. One of the finest examples of these three appeals in play is in the essay titled Letter from a Birmingham Jail by Dr. Martin Luther King Jr.
