Sublimation can occur because solids have
a. a melting point.
b. a vapor pressure.
c. a boiling point.
d. a triple point.

Based on this map, which statement about africa’s economic activity is most accurate? a) coastal countries are all members of opec b) economic development is more common with opec nations c) coastal countries have more access to productive resources d) economic development is more common above the sahara desert

What major factors play a role in global warming? 1. human activity and normal climate conditions 2. natural factors and human activity 3. normal climate conditions and abnormal human activities 4. abnormal human activities and natural factors

In russia which of these challenges affects the transportation of both petroleum products and other goods? a poorly repaired roads b harsh weather and vast distances c frozen waterways d separatist movements