MS-LS1-3: Body Systems Working Together
Also called NGSS MS-LS1-3 · Topic: Structure, Function, and Information Processing · Life Science
The Official Wording
Use argument supported by evidence for how the body is a system of interacting subsystems composed of groups of cells.
Clarification statement: Emphasis is on the conceptual understanding that cells form tissues and tissues form organs specialized for particular body functions. Examples could include the interaction of subsystems within a system and the normal functioning of those systems.
Assessment boundary: Assessment does not include the mechanism of one body system independent of others. Assessment is limited to the circulatory, excretory, digestive, respiratory, muscular, and nervous systems.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What MS-LS1-3 Means in Plain English
Students argue from evidence that the body works as a team of systems. Cells group into tissues, tissues build organs, and organs form systems such as the circulatory, respiratory and muscular systems, which depend on one another during everyday activities like running.
The focus is on how systems interact, not on how any single system works alone, and it covers six systems: nervous, muscular, circulatory, respiratory, digestive and excretory. This builds on cells (MS-LS1-1) and leads to feedback and balance in HS-LS1-3.
MS-LS1-3 I Can Statements
- I can explain how cells, tissues and organs build a system.
- I can use evidence to show two body systems working together.
- I can describe what happens when one system cannot keep up.
MS-LS1-3 Worked Example
A fatigue test a class can run with clothespins, a timer and one arm raised overhead.
Does a hand tire faster when it is raised above the heart?
Set It Up: A wooden spring clothespin for each student, a timer and a class data table.
- With the arm hanging down, squeeze the clothespin between thumb and finger as many times as you can in 30 seconds.Arm down: 58 squeezes
- Rest one minute, then repeat with the same hand raised straight overhead.Arm up: 41 squeezes
- Rest again, then do a second round in each position.Arm down 52, arm up 33
- Describe how the hand feels in each position.Raised hand burns and tires sooner
- Pool the class data and compare the averages.Raised arm: about 30% fewer squeezes
Squeeze counts fell faster with the arm raised, when the heart must pump uphill to supply the hand.
Why it works: Hand muscles need a steady oxygen supply, taken in by the lungs and pumped by the heart, so they tire sooner when that supply slows.
Common Mistakes with MS-LS1-3
Treating each system as separate
“Running only uses the muscles.”
Try this: Running also needs the nervous system to signal muscles, the lungs to bring in oxygen and the heart to deliver it.
Mixing up levels of organization
“The heart is a tissue.”
Try this: Cells form tissues, and tissues form organs. The heart is an organ made of muscle, nerve and connective tissue working together.
Making a claim with no evidence
“My arm got tired because it's tired.”
Try this: Point to data, like the drop in squeeze counts with the arm raised, and explain which systems the data connects.
Where MS-LS1-3 Fits
Practice MS-LS1-3
Quick Check
- Why do you breathe harder when you run?
- Put these in order from smallest to largest: organ, cell, system, tissue.
- Name two systems that work together after you eat a meal.