What is the difference between explicit and implicit costs

What is the difference between explicit and implicit costs
What is the difference between explicit and implicit costs? Which of the costs is most closely associated with opportunity costs and why? Give three examples of each type of costs that you have incurred over the past 30 days.
State and explain the law of diminishing returns. How might this law apply if you were studying for an examination for an online course?
Suppose that 0 workers generate 0 output, 1 worker generates 8 units of output, 2 workers generate 20, 3 workers generate 35, 4 workers generate 45, and 5 workers generate 47 units of output, 6 workers generate 47 units of output, while 7 workers generate 44 units of output. Show all work.

Calculate the MP and the AP for each worker
Clearly and accurately graph the TP, MP and AP curves.
At what point do diminishing returns set in? How would we know this had occurred?