Homeostasis, Feedback & Interacting Systems — Drills · Grade 7 Science
Chapter: Coordination, Defense & ReproductionWhat these drills covers
By the end of Homeostasis, Feedback & Interacting Systems you should be able to:
- I can explain homeostasis, feedback & interacting systems.
- I can use evidence, a model, and stated assumptions to support a biological explanation.
4 questions, multiple choice, numeric and written answer, each with a worked explanation.
Vocabulary used: homeostasis, feedback, negative feedback, hormone, target cell.
Problem 1
Which illustrates negative feedback?
- A response counteracts the original rise
- A number is called negative
- Every signal stops
- The deviation is always amplified
Answer and explanation
A response counteracts the original rise
The defining relationship is opposition to the initial deviation.
Problem 2
A model quantity rises to 18 units, then falls to 13. Find the response-period change.
Answer and explanation
-5 units
13−18=−5 units.
Problem 3
Does homeostasis require the same number at every instant?
Answer and explanation
No. Regulation can maintain functioning ranges while values vary with conditions.
Problem 4
Why should a hormone model show responsive target cells?
Answer and explanation
Cells differ in their ability to respond to a particular signal; transport everywhere does not mean the same response everywhere.