MediumBiologyHigh School (9–10)GeneralEcology and Environment › Pollution and ConservationConceptual
A cotton shirt buried in soil is gone in a few months, but a plastic bag buried beside it is still…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A cotton shirt buried in soil is gone in a few months, but a plastic bag buried beside it is still there years later. Explain the difference, and give one way the plastic bag can harm living things.
Need a reminder? The key ideaShow
Biodegradable substances are broken down by decomposers, whose enzymes act only on certain substances; non-biodegradable ones, such as plastics, glass and metal cans, last for a very long time. They block drains, harm animals and can build up in food chains.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The cotton. Cotton is a natural material. Decomposers have enzymes that break it down.
Step 2. The plastic. Each enzyme acts only on certain substances. Decomposers have none for plastics, so the bag stays.
Step 3. The harm. A cow that eats the bag with food scraps cannot digest it, and its gut can be blocked.
Answer: decomposers' enzymes break down cotton but not plastic; plastic can harm animals that eat it.
Discussion (0)
Log in to join the discussion.
Loading…