Why is celery tough to chew and break up?

Celery is tough to chew and break up primarily due to its high cellulose content, which is a structural component of plant cell walls. The long, fibrous strands of cellulose give celery its crisp texture but also make it more challenging to bite through. Additionally, the tightly packed fibers require more effort to break down compared to softer vegetables. This toughness is part of what makes celery a crunchy and satisfying snack, but it can also make it difficult to chew.