Waste as a Resource: teacher key

Poop and Pee, grade 10 edition, written for 10th grade. Waste is not just the end of a process: whale poop carries iron, wombat intestines mold cubes, and kidneys recycle 99 percent of what they filter. Here is how it works and what is still open.

Read the book. Print this page for the key.

Questions and answers

1. What did scientists find in all five whale poop samples they analyzed?
   • Cubes
   • Iron (answer)
   • Bile
2. What is still not known about the iron in whale poop?
   • Where the ligands that make it usable come from (answer)
   • Whether whales have kidneys
   • How many quarts they make
3. About what share of the fluid the kidneys filter goes back into the blood?
   • About 1 percent
   • Well over 98 percent (answer)
   • About half
4. Why did the experiment with beads and mimic intestines matter?
   • It showed the anus makes the cube
   • It showed shoving alone does not make cubes (answer)
   • It showed bile makes cubes
5. What do sphincters do?
   • Make bile
   • Filter blood
   • Hold an opening closed (answer)

Words

• sphincters: ring-shaped muscles
• microbiome: gut bacteria community
• reabsorption: taking back in
• ligands: binding molecules
• emulsify: break into droplets