cucumber is a acidic vegetable it has been around for more than 4000 years which sentens is it run-on sentence or correct sentens of fragment?

Here are some possible corrections for the run-on sentence:

The cucumber is an acidic vegetable. It has been around for more than 4,000 years.

OR

The cucumber is an acidic vegetable; it has been around for more than 4,000 years.

OR

The cucumber, an acidic vegetable, has been around for more than 4,000 years.

OR

The cucumber is an acidic vegetable that has been around for more than 4,000 years.

OR

The cucumber is an acidic, 4,000-year-old vegetable.

The rising action is where the main event is escalading, usually the best part of the book!

Explanation:

Think of it as a rollercoaster, the rising action would be the tippy top of the rollercoaster, before it comes to an end