An igneous rock that contains mostly pyroxene and olivine has what type of composistion

How would i answer this for an exam?

Why have the countries of the region had difficulty establishing democratic governments in recent years? choose all answers that are correct b is also correct i need to know if theres any morecommunists have overtaken the countries of the caucasus region. the soviets established national borders in the region without considering the location of ethnic groups. fighting continues between armenia and azerbaijan over the nagorno-karabakh region. civil war between communists and islamic groups in tajikistan resulted in thousands of deaths and refugees are forced to flee. in a test!

How did geographic isolation affect the islands in the australasia ecozobne?