What barriers prevented plants, animals, and people from reaching north america? how were the barriers overcome?

Three broad zones with different climates and resources shape russian life. they include:

What event from world war l does the image most likely depict

Enlightenment thinkers most contributed to the development of whichpolitical idea? a. religious leaders should play the largest role in establishing asociety's laws. b. democratic governments have the responsibility to protect humanrights. c. criminals must be punished harshly if a society is to maintainorder. d. written constitutions place unnecessary restrictions ongovernments' powers.