Body organization
Subsystem
Key Organ
System Interacting
Misc
100

The basic unit of structure and function in a living thing.

Cell

100

This system's main job is to exchange oxygen and carbon dioxide between the blood and the air.

What is the Respiratory System? 

100

The key organ of the skeletal system that provides the body's structure.

What is a bone?

100

The Respiratory System brings in oxygen, and this system is responsible for delivering that oxygen to every cell in the body.

What is the Circulatory (or Cardiovascular) System?

100

The maintenance of a stable internal environment in the body, regardless of changes in the external environment.


What is homeostasis?

200

A group of similar cells working together to perform a specific function, like muscle or nerve.

What is a tissue?

200

This system is responsible for all forms of voluntary movement, as well as the involuntary movements of the heart and internal organs.

What is the Muscular System?

200

The main organ that pumps blood in the circulatory system.

What is the heart?

200

When you run, your Muscular System needs more oxygen, so it sends signals through this system to increase your heart rate.

What is the Nervous System?

200

 This type of tissue is specialized for contraction and allows for movement.


What is muscle tissue?

300

The smallest level in the body organization hierarchy that is considered alive and can perform all life functions.

What is a cell? 

300

This system transports blood, which carries oxygen, nutrients, and waste, to and from all parts of the body.

What is the circulatory system ? 

300

These two spongy organs are the primary site of gas exchange in the respiratory system.


What are the lungs?

300

After the Digestive System breaks down a sandwich, the nutrients are absorbed into the bloodstream of this system for transport.

What is the Circulatory (or Cardiovascular) System? 


300

The protective organ that is the largest by mass in the human body.

what is skin?

400

The level of organization higher than a tissue but lower than an organ system, often featuring multiple tissue types, such as the stomach or the brain.


What is an Organ? 
400

The process this system performs to break down food into usable nutrients and absorb them into the bloodstream.

What is the Digestive System? 
400

The control center of the nervous system that processes information and directs action.

What is the brain? 


400

This system, made of bones, stores calcium, which is a vital mineral needed for your Muscular System to contract.

What is the Skeletal System?

400

The two main organ systems responsible for communication and control of the entire body.

What are the Nervous System and the Endocrine System?

500

The correct order of organizational levels from smallest to largest: Cell, Organ System, Organ, Tissue.

What is Cell, Tissue, Organ, Organ System?

500

This system, which includes the kidneys and bladder, works to filter waste products from the blood and remove them as urine.

What is the Excretory (or Urinary) System?

500

 The large organ in the digestive system responsible for producing bile and detoxifying blood.


What is the liver?

500

The kidneys are part of the Excretory/Urinary System, which cleans waste from the blood provided by this system, ensuring the blood is purified.

What is the Circulatory (or Cardiovascular) System?

500

The small, finger-like projections in the small intestine that greatly increase the surface area for nutrient absorption.

 What are villi?