You're very close! The microscopic building blocks of tissues and organs are cells.

Here's a breakdown:

* Cells: The basic unit of life. Each cell is a self-contained entity with its own internal structures and functions.

* Tissues: Groups of similar cells that work together to perform a specific function. Examples include muscle tissue, nervous tissue, and connective tissue.

* Organs: Structures made up of different tissues that work together for a common purpose. Examples include the heart, lungs, and stomach.

So, while tissues and organs are made up of microscopic components, those components are specifically cells.