during a class experiment, students passed gas x over heated copper metal, the metal changed its colour to black. Identify gas x?​

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.

Anions are negative charged ions

Nonmetal are moldable and easily shaped

1. why does the same side of the moon always face earthc.the rotational period of the moon is equal to one revolution around earth2. which is greater the moons period of rotation or its period of revolution  b.the moons revolution period around earth3.what was the major accomplishment of the apollo missions  c.sending the first human into space4. which of these space missions involved the deployment of lunar roversa. voyager 15. which scientists are going to explore next on kepler-186fd. evidence of existence of life6.which mission is not going to explore the outside of the solar  systemb.safir7.which technology limit the future of space explorationb. scientist must first develop certain technologies before missions can be completed.