Meaning "to care for" or "to look after":
* Attend: To be present at an event.
* Tendency: A natural inclination or disposition.
* Attendant: A person who attends to or serves another.
* Intendant: A person who manages or supervises.
* Superintendent: A person who oversees a particular activity or department.
Meaning "to stretch" or "to extend":
* Extend: To make longer or wider.
* Tendril: A slender, twisting stem that clings to a support.
* Tendon: A strong, fibrous cord that connects a muscle to a bone.
* Attenuate: To make thinner or weaker.
Other related words:
* Attentive: Paying close attention.
* Intention: A plan or purpose.
* Pretend: To act as if something is true when it is not.
* Tender: Soft, delicate, or sensitive.
* Tenderness: The quality of being gentle, caring, or compassionate.
This is not an exhaustive list, but it gives you a good starting point for understanding the different ways the root word "tend" can be used.