3. Historians used to think the Mayans were a peaceful society but have since changed their mind. What are at least TWO reasons that could have forced the Mayans to become more warlike?

Plants in the tundra biomes have had to adapt to live long periods of time without a. cool temperatures b. sunlight c. oxygen d. water

Which of the following types of nonrenewable fuel sources requires the storage of radioactive waste? a. coal b. nuclear c. solar d. oil

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