The speaker is describing the issue of plastic pollution in the oceans, the impact it has on mrine ecosystems, and the need to transition from a linear plastic production nd disposal system to a circular one.

2. Where do you think the place he ends up is?

The place the speaker ends up referring to is an ecosystem with dead zones coused by nutrient pollution, which results from industrial, agricultural, and urban waste entering the oceans.

3. How do you know it?

I can understand this from the text you provided, where the speaker talks about marine pollution in various forms, including nutrient pollution from industrial, agricultural, and urban waste, leading to ded zones in marine ecosystem. The next also emphasizes the importance of changing practices across various sector's to address these issues.

(TribunNewsmaker.com/berbagai sumber)