All laundry detergents contain surfactants, which can harm aquatic life. However, the environmental effects of most i...

shunhe on June 13, 2020

Hi @marissa,

Thanks for the question! So let’s take a look at what this stimulus is telling us. All laundry detergents have surfactants, which can harm aquatic life (and are thus damaging to the environment). Then we’re told that the environmental effects of most ingredients in laundry detergents, including “ecologically friendly” ones, are unknown. The author then concludes that there is no reason at all to support the idea that laundry detergents advertised as ecologically friendly are less damaging than other laundry detergents.

Now we look for an answer choice that weakens the argument. (A) tells us that laundry detergents have fewer surfactants on average than other detergents. If this is the case, then they have less of something that is environmentally bad, which makes them less environmentally damaging. We can’t just assume that they have more other bad substances, and so (A) weakens the argument.

(B) does not weaken the argument, since it just tells us that there’s no reason to suppose most ingredients in non eco-friendly laundry detergents harm the environment significantly. This doesn’t help weaken the argument concluding that eco-friendly laundry detergents aren’t less damaging than other ones.

(C) doesn’t weaken the argument, since it just tells us different laundry detergents have different kinds of surfactants which have different effects, but don’t tell us if there’s a difference between eco-friendly and non eco-friendly, so it doesn’t give us enough information.

(D) doesn’t weaken the argument, since there’s no reason to assume that eco-friendly laundry detergents would have fewer of these other bad ingredients than other laundry detergents.

(E) doesn’t weaken the argument, since it actually seems to strengthen the author’s conclusion, since if you have to use more laundry detergent, then it’s probably even more likely that it harms the environment, and (E) tells us that you have to use more eco-friendly laundry detergent than normal detergent.

Hope this helps! Feel free to ask any other questions that you might have.