Internal Systems of Living Things

The systems inside the body and the jobs they do to keep an organism alive.

9 questions, free, marked as you go with a worked explanation on every one.

What this covers

What is the main job of the digestive system?
Which organ pumps blood around the body?
Which of these are jobs of the skeletal system? Select all that apply.
What happens in the lungs?
Why must the circulatory and respiratory systems work together?
What is the job of roots and the stem inside a plant?
A student takes her pulse to check how her circulatory system is working. She counts 18 heartbeats in 15 seconds. What is her heart rate, in beats per minute?
Muscles at a joint such as the elbow work in pairs. Why is a second muscle needed to straighten the arm after the first one has bent it?
Use the table. Which system's job is to break down the food a person eats?