Explanation:

- The passage discusses the concept of challenges and the positive outcomes they can bring.

- Blank (1) refers to challenges as something that arrives at our doorstep, suggesting a metaphorical approach to how challenges present themselves.

- Blank (2) requires a term that reflects overcoming obstacles, indicating that though it may seem tough, the act of facing challenges is ultimately beneficial.

- Blank (3) implies the absence of challenges would result in no progress, growth, or achievements in life.

- Blank (4) specifically refers to utilizing a certain personal quality maximally in the face of challenges.

- Option 1: "job" – Doesn't fit as it refers to employment, not personal traits or qualities.

- Option 2: "potential" – Best fits, as it refers to using one’s abilities or qualities to the fullest.

- Option 3: "work" – Refers to tasks or efforts, but not directly linked to personal traits.

- Option 4: "time" – Incorrect as it refers to duration, not personal capabilities.

- Blank (5) indicates the necessary attributes needed to overcome challenges effectively, typically involving personal growth factors.