"B" strengthens the statement if it was referring to "the effects of weed-killer on local soil are probably misleading", but I interpreted it as the effects of weed-killer in general and not the "effectiveness."

In fact, I thought "B" weakens the argument, since it outlines controlled conditions that determine the "effects of the weed-killer" in which one can be more confident with the "effects".

@ConnerKline In this example, wow would you distinguish between

Most X are (Y and Z) versus most X are Y, most X are Z?

@KevinLin I'm a little stuck on the "tend to", so I want to know if there are ways to change Q1 into a causal statement? or Q2 into a non-causal sentence?

E.g., On every high school basketball team, the best players tend to become the most popular people at school.

Children that are given everything they ask for tend to be individuals who are unable to cope with life's challenges?

Thanks for the help!

What is Q1 was phrased as "...., the best players are the most popular"? Would it still be not causal?