Grammar

Hello, I have three questions related to the grammar in the following sentences.

If you answer my questions, I thank you for answering.

1) Recycling is not a perfect way to manage waste. It still requires large amounts of energy to purify used resources and convert them into new products. So, [how/what] about trying to creatively reuse, or “upcycle,” them instead? This new approach is becoming more popular since it is even more environmentally friendly than recycling.

Q; In the above sentence, which is correct, ‘how’ or ‘what’?

Please answer.

2) These bags are perfect for bicyclists going to work every day in all kinds of weather.

Q: In the above sentence, is ‘to go’ instead of‘going’ correct?

3) A shocking number of tires get thrown away there every year, and they are a serious environmental problem since they cannot decompose or be recycled. To solve this problem, Parsons and his team are turning them into sandal bottoms. They then use canvas and natural materials to make the other sandal parts. What a great reuse of resources [it is/they are]!

Q: In the above sentence, which one is correct,‘it is’ or ‘they are’?

Please reply. Thank you!