Here's why:

* Tissue is a group of similar cells that work together to perform a specific function.

* Specialized cells within a tissue are often responsible for producing and secreting particular materials.

For example:

* Connective tissue contains cells that produce collagen and other fibers, forming the structural framework of the body.

* Glandular tissue contains cells that synthesize and secrete hormones, enzymes, or other substances.

Let me know if you have more questions!