RC Question 3 Explanation
DISCUSSION: The rate of growth is a constant 9.5 mm per century. This is useful because it lets us measure how long lichen has been growing. For example, 95 mm of lichen would be 1000 years old.
Read the lines above and below lines 29-30 to get the full context.
___________
- The growth rate isn’t relevant to how fast lichen establish themselves. There’s a difference between starting to grow, and growing.
- The passage doesn’t say that 9.5 mm per year is a slow speed.
- Environmental conditions are only mentioned on lines 54-58.
- The passage never says why lichenometry doesn’t work well for earthquakes older than 500 years.
- CORRECT. This is the best explanation. The author just wants to illustrate how fast lichen grows.
Hi! For B, from line 27 we know lichens grow at a slow rate and that would include this species in North American. However, we don’t know if this one is the slowest.
Yes, that’s correct! Thanks for catching this — the passage does indeed imply that this is a slow rate. This answer choice is incorrect because we don’t have evidence to indicate that this particular lichen has the slowest rate of growth.