The principle of fossil succession states that:

a. fossil species found in rock are the same as species living today.
b. every fossil species spans only a limited range of rock layers, corresponding to the time period over which it lived.
c. every rock layer contains only one species of fossil.
d. the same fossil assemblages appear throughout geologic time in a repeating intervals.

B. Every fossil species spans only a limited range of rock layers, corresponding to the time period over which it lived

Explanation:

A. Fossil species found in rock are the same as species living today:  This is incorrect as the fossil record contradicts that statement.  

C. Every rock layer contains only one species of fossil:  Example, Ghost Ranch, New Mexico United States. The locality is famous for the Coelophysis quarry which contains the fossils of a Bipedal Triassic dinosaur, the  Coelophysis. Other fish fossils were located in the bone bed with the Coelophysis. This contradicts the above claim.

D. The same fossil assemblages appear throughout geologic time in a repeating intervals: Although some rock types do repeat in certain areas they usually don't contain the same fossils unless the rock types repeat in the same group of rock formations in the same time period even than fossils don't always last the whole period. One way of age dating rock formations is worked out by using different fossils and is called Biostratigraphy. This only works because different time periods contain different fossils.  

Greatest - Denmark

Least - U.S.

Step-by-step explanation:

U.S. - 272,648,000/9,364,520=29.12 people per square km

Denmark - 5,248,000/42,077=124.72 people per square km

Ghana - 18,339,000/237,533=77.21 people per square km