Year 8 Science · Unit 1 · Lesson 18
Challenge Worksheet
Learning Goals
Find the mistake
Read the student essay below carefully. It contains five errors spanning multiple unit topics. Find them all, then answer the questions on the next page.
A student wrote this essay about how the body's systems work together
"The human body is organised from cells into tissues, organs and whole organ systems. The circulatory system transports materials around the body using blood. [Sentence A] In this system, the lungs act as the pump that pushes blood through the blood vessels."
"The body also needs to take in and break down food. [Sentence B] Most digestion of food into small, absorbable molecules takes place in the lungs. Once absorbed, these nutrients are carried to cells by the circulatory system, which shows how the digestive and circulatory systems work together."
"The excretory system removes waste from the body. [Sentence C] The kidneys filter nitrogen-containing wastes such as urea from the blood and expel them in urine. The lungs also act as excretory organs, they remove oxygen from the blood, which would otherwise build up to toxic levels."
"Gas exchange in the lungs occurs across the alveoli. [Sentence D] Oxygen diffuses from the alveoli into the blood because there is a higher concentration of oxygen in the blood than in the alveoli. Carbon dioxide diffuses in the opposite direction."
"Finally, the interdependence of body systems means that a disruption in one system always causes total system failure. [Sentence E] For example, if the circulatory system slows, every other system immediately stops working completely."
1. Identify all five errors. For each, state which sentence it is in (A–E) and briefly describe what is wrong.
2. Rewrite Sentence C correctly. Your rewrite must accurately describe what the lungs excrete and why removing it matters for the body.
1. Rewrite Sentence E more accurately. Explain the difference between "disruption causes system stress" and "disruption causes complete system failure."
2. Sentences A and E both involve more than one body system. Explain why errors that span several systems can be harder to spot than errors about a single system. Use an example from the essay to support your answer.
Wrap Up
In one sentence, why does a strong capstone response need to draw on multiple unit topics, not just one?