Explain why people, who inherit one mutated allele of the brca1 gene have a higher likelihood of developing cancer\

BRCA1 gene is a tumor suppressor gene that can repair damaged DNA. Loss of BRCA1 gene will decrease the DNA repair, thus increasing the DNA damage. When exposed to free radical, the DNA can be damaged and the damage will accumulate. When the damage hit some area that regulating the cell replication, the cell can become cancer.  

Balkan nationalism increased tensions between austria and russia

Cis correct i think