Here's why:
* Action verbs describe an action being performed. In the sentence "I visited the museum," the subject (I) is performing the action of visiting.
* Linking verbs connect the subject to a noun or adjective that renames or describes the subject. Examples of linking verbs include "is," "am," "are," "was," "were," "seems," "feels," etc.
Let me know if you'd like more examples!