Explain Robert Brown (1833) was the first to describe the nucleus. Why was he the first to recognize the importance? When looking at new discoveries, how do you decide what is important? What is the role of chance in scientific discoveries?

When looking at cells, many observers had described the structure of the nucleus but never attached importance to this structure. Robert Brown (1833) was the first to describe the nucleus. Why was he the first to recognize the importance? When looking at new discoveries, how do you decide what is important? What is the role of chance in scientific discoveries?