K-5 friendly lesson
One small step at a time.Read the idea, try the activity, and celebrate each win as you go.

Body Building Blocks

Your body is built from tiny cells that team up!

Do this: Read the concept below, then try the quiz or activity.

Lesson 1 of 18

Concept

Cells join to form tissues. Tissues build organs. Organs work together in systems to keep you alive and active.

Concept Check

Which is the smallest?

Put the levels in order

These steps are out of order — can you fix them?

1.Organs
2.Systems
3.Cells
4.Tissues

Quick Terms

1 / 3
Cell
(Click to flip)
The smallest living building block
(Click to flip back)

From Small to Big

Cells
Tissues
Organs
Systems