The table below shows some physical properties of two unknown samples. physical properties sample mass solubility (in water) c 200 g 36 g/ml d 500 g 180 g/ml what would best support whether the two samples are of the same substance or not?   the two substances are the same because the property that depends on the amount of the sample is different.  the two substances are the same because the property that is independent of the amount of the sample is different.  the two substances are not the same because the property that is independent of the amount of the sample is different.  the two substances are not the same because the property that depends on the amount of the sample is different.

The answer would be: The two substances are not the same because the property that is independent of the amount of the sample is different. 

The two substances has different solubility which is 36 g/mL and 180 g/mL. The same kind of molecule should have same density and solubility, regardless the mass of the sample. In this case, the substances are not same since it has different solubility.

Answer: abeexplanation:

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

Ithink is d. physical property