Kidneys, Excretion & Internal Balance — Drills · Grade 7 Science
Chapter: Body Organization, Transport & MovementWhat these drills covers
By the end of Kidneys, Excretion & Internal Balance you should be able to:
- I can explain kidneys, excretion & internal balance.
- 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: excretion, filtration, reabsorption, urine, metabolism.
Problem 1
Which material can be excreted through lungs?
- Carbon dioxide
- Every chromosome
- Whole bone
- Every unabsorbed food piece
Answer and explanation
Carbon dioxide
Carbon dioxide produced in cellular metabolism can be transported to lungs and released.
Problem 2
A model returns 45 of 50 filtered units. What percent returns?
Answer and explanation
90 %
45/50×100=90%, for the invented model.
Problem 3
Why is excretion not identical to eliminating unabsorbed food?
Answer and explanation
Excretion removes wastes produced by metabolism; unabsorbed food is material that did not enter those cellular pathways.
Problem 4
Why must a model’s interval be stated?
Answer and explanation
Input and output amounts are comparable only when they refer to the same period and boundary.