Here's why:

* Found in plants: Cellulose is the primary structural component of plant cell walls, making it the most abundant organic compound on Earth.

* Vast quantities: Plants produce massive amounts of cellulose, and it's estimated that about 100 billion tons are produced annually.

* Diverse applications: Cellulose is used in paper, textiles, and various other products.

While other natural polymers like lignin and chitin are also abundant, they are not as prevalent as cellulose.