CLEAN : Residents mourn and lay flowers after Hong Kong student's death

The video begins with a humorous remark, setting a light-hearted tone for the tutorial.

What is the initial topic discussed in the video?

• The importance of laughter

• A personal story

• A scientific explanation

• A joke

What does the speaker mention after introducing laughter?

• A famous quote

• A scientific study

• A personal experience

• A historical fact