Which of the following themes differentiates the modern era from other historical periods

Which of the following regions has what is considered the most rugged terrain in oklahoma? a. the wichita mountains b. the arbuckle mountains c. the sandstone hills d. the ouachita mountains

[fw.02]sinkholes are often formed as a result of the actions of. a. heat on recharge b. pressure on aquifers c. acid in groundwater d. minerals in hot springs

Which barrier to economic development is shown in the following examples? i. the high rate of hiv infection in underdeveloped nations ii. the use of children as soldiers in uganda’s army in the early 2000s iii. low literacy rates in underdeveloped nations with limited exposure to adequate education a. foreign debt b. political instability c. widespread disease d. low levels of social welfare