Answer:
When Harry asks "What is different with this plant that does not grow very well compared with the other house plants?"
Step-by-step explanation:
When Harry saw that one of his houseplants does not grow very well it was an observation. This observation brought forward the problem which was the question that "What is different with this plant that does not grow very well compared with the other house plants?"
To get an answer for this question, Harry can devise a hypothesis based on his information from the internet and perform experiments. Then he can make conclusions about his result.