Specific gravity is a number representing the ratio of a mineral's weight to the weight of an equal volume of water. true false

True

Explanation: Specific Gravity of a body, also called its Relative Density, is the ratio of the density of that body to the density of a reference material (usually water).

With the Mathematics done right, it is evident that the specific gravity of a body would be equal to the ratio of mass/weight of the body to the mass/weight of an equal volume of water.

S.G = (Density of body)/(Density of water)

Density of Body = (mass/weight of body)/(volume of body)

Density of water = (mass/weight of water)/(volume of water)

If volume of Body = Volume of water, then,

S.G = (Mass/Weight of body)/(Mass/Weight of equal volume of water)

Proved!!

heat or electricity in the atmosphere- c.

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.