Cambrian seas A. were at an all-time low level during the whole of the period. B. rarely encroached on the land and thus marine deposits are rare. C. did not cover much land area due to continued orogenic activity. D. were widespread due to many low-lying land masses.

D. were widespread due to many low-lying land masses.

Explanation:

Cambrian Period was the first geological period of the Paleozoic Era, it occurred between two ice ages; Proterozoic and Ordovician. During these era, there were mass extinctions due to the decrease in global temperature.

Cambrian seas were widespread due to many low-lying land masses.

central asia and the south caucasus are important because their orientation will greatly affect the power and national security planning of large neighboring or interested states (principally, the united states, russia, china, iran, turkey, india, and pakistan). how these states and others think and act strategically in central asia and the south caucasus will influence geopolitical alignments in the region. it is also important to grasp how these states, and others whose interest is acute though less direct (for example, israel, japan, south korea, some gulf arab states), factor central asia and the south caucasus into their strategic thinking.

conversely, the states of central asia and the south caucasus are increasingly dealing with countries other than those we tend to see as having the most direct interest and natural advantages--russia, iran, and turkey. the states of central asia and the south caucasus are looking to a number of other states--for example, india, pakistan, israel, china, south korea and japan--for new trade possibilities and security arrangements. all of these states are increasingly active in both central asia and the south caucasus.

strategic dynamics now cascade across geographic regions. developments in one region can have extensive direct, and second- and third-order consequences other regions. analysts must broaden their focus and not view the region as a traditionally defined set of states. central asia and the south caucasus are a strategic crossroads. they must be understood and analyzed in the larger eurasian/asian context if analysts are to capture all of the cross-regional dynamics that shape these two regions as well as the broader geopolitical landscape around them.

iran is potentially the most influential near-term variable. if a normalization of us-iranian relations takes place, the entire regional picture would change dramatically by changing the strategic calculations of all the regional actors and the major external actors in the two region.

russia's policy will not necessarily be more coherent or benign under president putin. russia probably will continue to be weak but remain relatively stronger than its neighbors and possess more leverage than other actors in the central asian and south caucasus regions. several panelists suggested considering the implications for central asia and the south caucasus of a russia in which power is significantly devolved to its borderlands, or that is even fragmented politically.

so long as afghanistan remains in chaos, which it probably will for a fairly long time, it will be a principal contributor to the most worrisome threats facing central asia: the conjunction of narcotrafficking and militant islam, terrorism, and political instability.