US soldiers badly injured in new attack on Humvee

The video begins with a greeting and a brief conversation with Bob, followed by an introduction to the topic of public health.

How would you describe the tone of the text?

• Formal

• Casual

• Serious

• Humorous

What can be inferred about the relationship between the speaker and Bob?

• They are friends

• They are strangers

• They are colleagues

• They are family