A woman treated her home with a pesticide that kills spiders. The first application killed 78% of the spiders. Two months later she applied the pesticide again, but it only killed 45% of the spiders. What would best explain the decrease in the effectiveness of the pesticide?

Question

destinymasha · Answer

the spiders have become resistant to it.

beccaboo333 · Answer

Agreed^ the spiders started to develop an immunity towards it all

beccaboo333 · Answer

Welcome to OpenStudy as well.

anonymous · Answer

The spiders which did not succumb to the first application were such that they were less susceptible to the chemical. "Immunity" suggests individuals picked up the ability to fight off the chemical, but it may just be that we killed the weaklings first, and the others were unchanged, just hardier to begin with.

anonymous · Answer

one word best answer is ' Natural Selection' as Darwin stated.

anonymous · Answer

Yes, this would be an example of natural selection.

anonymous · Answer

guess , there can be various reasons for e.x ++1.>it expired 
2>the total amount was 78+45 + 145
3 > the spiders developed an immunity towards the acid.. 


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