Lesson 5 of 16
The second time
Show on a big screenDoes a body fight the same germ the same way twice?
On a graph, an axis is a line that carries numbers. A peak is the highest point of a line.
Step 1 of 4
- Axis: amount of germs, against time.
- First meeting: the line climbs slowly, peaks high.
- Second meeting: the line stops climbing sooner, and peaks low.
- Both come back down.
No. The second time, the body usually starts fighting sooner.
Acquired immunity is the body's memory of a germ or vaccine.
The rule
A body that met a germ usually fights it sooner next time. Then it gets less ill. The germ has not changed. The body starts fighting earlier. This protection is called acquired immunity.
The body remembers the germ, so it starts fighting sooner. Defenders are the parts of the body that fight a germ.
| Meeting | Defenders start | Peak |
|---|---|---|
| First | Late | High |
| Second | Early | Low |
This is arithmetic in made-up units, not a real body.
Slide the start day. Compare the two peaks.
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