Answer:
Variation in income in all three types of profession is due to different skills.
Explanation:
A computer engineer whose work is less risky due to which his income is also less.
Unlike a computer engineer, a chemical engineer who works in a nuclear lab performs more risky tasks and earns a higher income.
Unlike these two, the civil engineer who handles the responsibility of bridge safety performs the riskiest tasks for which he also needs high-quality skills, due to which one can get the most income.