What is the role of <b>project</b> <u>development</u>?

In HTML5:

<b> is for bold text without any other distinction(your ex:project). 

<u>it shows an underlined text (your ex:development), it is for a text that should be stylistically different from normal text where sense is not precise like misspelled words.

Project development has to be with the different phases from definition to start up, so in every one of this phases project manager or project or project coordinator has to follow project program and cover the scope defined for phases.