Cells, Tissues, and Organs: How Your Body Is Built

Science · The Human Body · ages 7-9

Name ______________________ Date ____________

You can see a single cell just by looking closely, without a microscope.
Circle one: True False
What is the smallest living building block of your body?
- A cell
- An organ
- A tissue
Which order goes correctly from smallest to biggest?
- Cell, tissue, organ, organ system
- Organ, cell, tissue, organ system
- Tissue, organ, cell, organ system
Tiny muscle cells group together to make muscle tissue. What does that muscle tissue help build next?
- One single new cell
- An organ, like the heart
- A whole new body
Look at the chain: cell to blank to organ to organ system. What goes in the blank?
- Tissue
- Bone
- Blood
Why do you need a microscope to see a single cell?
- Cells hide inside your bones
- Cells only come out at night
- Cells are far too small for your eyes to see alone
Leo says, 'My heart is just one giant cell.' What is wrong with what Leo said?
- The heart has no cells inside it
- The heart is smaller than a single cell
- The heart is made of many muscle cells grouped into tissue, not one giant cell
Maya says, 'The heart is a tissue because it is part of my body.' What is wrong with Maya's idea?
- The heart is actually a single cell
- The heart is an organ, built from tissues, not a tissue itself
- The heart is bigger than the whole body

Answer key

For grown-ups. Fold this page away before handing over the rest.

False · Cells are so small that you need a microscope to see even one of them.
A cell · Cells are the tiny living pieces that build everything in your body, including organs like the heart.
Cell, tissue, organ, organ system · Cells are the smallest, then they group into tissues, then organs, then whole organ systems.
An organ, like the heart · Muscle tissue, along with other tissues, joins together to build an organ, like the heart.
Tissue · A tissue is a group of similar cells working together. It fits right between a single cell and a whole organ.
Cells are far too small for your eyes to see alone · A single cell is far too tiny for your eyes alone, so scientists use a microscope to see it.
The heart is made of many muscle cells grouped into tissue, not one giant cell · The heart is made of many tiny muscle cells grouped into tissue, not just one giant cell.
The heart is an organ, built from tissues, not a tissue itself · The heart is an organ. It is built from tissues, which are built from cells, so it is not a tissue by itself.