Which sentence in the introductory paragraph is the thesis statement?

Today, we are continuing to find ways to improve our lives, our health, and our home environment through the examples provided by nature.

Although this concept may seem new, biomimicry has been around for centuries.

These tires do not go flat, yet they have the same kind of feel and ride as air $-$ filled tires.

A Wisconsin company is making a tire that is not filled with pressurized air.

New technologies like this are emerging every day, and the key feature of these new designs is that they are based on things we see in nature.