PT15.S3.Q8 - Delta Green beetles

casablanca-1

I don't understand how AC A strengthens the argument...so we can't see them when it is a wet year, shouldn't that mean that in '85 the observer would have seen less beetles that year than in '89?

help

claremont

Not quite.

AC A says that when they don't move they're almost impossible to see.

Because 1989 was a relatively dry year we know they were less active than they were in 1985 and when they're less active they're less likely to be seen.

teechj117

To make the argument's conclusion more clear, we have to bring out what validates "Probably does not reflect a drop in population" between 1985 and 1989.

Consider the other answer choices

B - We aren't concerned about their habitat. This is outside the scope of the argument and doesn't connect us to the conclusion. In fact, this gives us more questions than a straight solution.

C- Again, outside the scope. We don't want to know when they move for food or anything about their reproductive habits, only what the observer did or did not see for those two years. The phenomena being introduced here could be possible, but it could be one of a number of reasons they did or did not move. Bottom line is, they have a higher activity when it's wet than when it's dry. Keep that in focus.

D - Although stated to be rare, rarity isn't the main concern. The dates given in this ac don't have much to do with the dates of our observation. Stick to the information that is given to us in the stimulus. Why was there more seen in the two years observations were recorded? Wet conditions, high activity. Dry conditions, less activity. These are our parameters for consideration.

E - This can be a tricky one. You might consider the presence of a predator to reinforce the level of activity. You could say that this is something not considered in the observation, that because NO predator relies on the beetle as it's major food supply, that this would strengthen the argument making the drop in population less probable. However, like B, this would give us more questions than one solution to reinforcing our argument. By introducing a possible scenario, we are creating more holes than patching what's given.

A is correct because it provides a solution to a hole in our argument: why were more beetles observed in 1985 than in 1989? Given the facts; the beetles can remain motionless for hours, and they remain less active in dry conditions. AC A gives us another reason why less of them were observed for that dry year as well as a connection to our conclusion: their population remained relatively intact despite less of them being observed in 1989 than 1985.

Hope this helps