Performing an experiment to determine whether listening to classical music while taking a quiz helps students do better. The researcher has two
comparable classrooms with one classroom of students taking a quiz while listening to
classical music and the other taking the same quiz without listening to classical music.

Where is the independent variable in this experiment

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3

the answer is 0.8m.

by: nicholas

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.