(CNN) -- The people of Southern Sudan started voting on January 9 on whether to become an independent country or remain part of Sudan, Africa's largest nation which has been wracked by decades of conflict.

So how have the people of Sudan reached the point where the country could split?

Sudan, which is a quarter the size of the United States but home to just 44 million people, was ravaged by civil war even before it gained independence from Britain in 1956. Decades of fighting, famine and factionalism followed with every horror imaginable. The referendum is a key provision of a 2005 peace treaty that ended a bloody north-south civil war in Sudan that killed 2 million people and displaced several million others, mainly from Southern Sudan, from 1983 to 2005. It pitted the powerful northern government of Arab Muslims against blacks in Southern Sudan who practice Christianity and animist religions.

What was the root cause of the conflict?

Southerners rebelled in 1955 against what they saw as domination from the north as the country neared independence. Nearly all jobs in the new national government went to northerners. The northern government later sought to impose sharia, or Islamic law, on the non-Muslim south. That further polarized the two sides. The war has had overtones of religious and racial conflict, but it's also a fight for power. One scholar has described it as a "clash of identities in competition over power and resources." The north-south conflict is separate from violence in the western Sudanese region of Darfur, which has undergone its own tentative peace process.

What is the likely outcome of the referendum and what is at stake?

Since the 2005 Comprehensive Peace Agreement, there has been a glimmer of hope that a permanent peace could be secured at the ballot box. A yes vote to secession, which many most analysts believe is the expected final result, could create Africa's newest nation.

Or it could plunge the country into renewed conflict if the Arab north Sudan refuses to abide by the results. Sudanese President Omar al-Bashir has said he will accept the results of a referendum, which international donors have given $58 million to a U.N. fund to finance. At stake is most of the oil wealth in Sudan, which is primarily located in the south but which must run through pipelines in the north to reach a port for export. If the south chooses independence, both sides would negotiate a variety of issues, including how to share oil revenue.

Where will voting take place?

The United Nations says more than 4 million ballots have been delivered for distribution across Southern Sudan, and in Khartoum, Sudan's capital, for southerners living in the north. The ballots, which carry two pictures -- one hand signifies independence; two hands, a unified Sudan -- have been printed in Britain. Southern Sudanese also are eligible to vote in Australia, Canada, Egypt, Ethiopia, Great Britain, Kenya, Uganda and the United States.

Do observers believe voting will be fair?

Many southerners fled to the north for safety in recent decades as one of Africa's longest running civil wars played out in their homeland. Khartoum itself has numerous voter registration facilities, and the deadline was extended by a week but southerners are wary, with many opting to leave town rather than sticking around to vote. A satellite surveillance project spearheaded by actor George Clooney's organization will monitor for violence in Sudan during the vote. The program will use satellite images to assess the situation on the ground for any signs of conflict, monitor hotspots in real time, and post the findings online, organizers said.

If the south does split, what are the dangers?

The main rebel force in the south, the Sudan People's Liberation Army has dominated politics in the south since the fighting ended in 2005. But the area is still awash with weapons, militias and mistrust. The whole process is precarious. Experts say a fresh conflict is a real possibility.

Alex Vines, of London-based think tank Chatham House, said: "The referendum is a risky affair. If it's managed wisely by leaderships of the south and north then maybe an amicable separation can take place. There's a lot of danger it could backfire spectacularly -- we could see a renewed civil war, which is nothing new for Sudan."

What is likely to happen in the rest of the country?

Bashir is already an international pariah -- he is wanted for genocide and crimes against humanity by the International Criminal Court -- for his alleged involvement in killings in Darfur, in the far west of the country. There, the Janjaweed militia, with government backing, has been engaged in a scorched earth policy, destroying villages, raping and killing, according to the United Nations, Western government and human-rights groups. More than 300,000 people have been killed in the desolate region, the United Nations says, though Sudan says the toll is lower. Hopes for peace have gone up and down over the last few months. If the south does go it alone, it may embolden rebels in Darfur who oppose Bashir's government in distant Khartoum. The Darfur region would remain in Sudan, not be a part of Southern Sudan.

There are also other challenges, such as what to do with displaced people, according to Vines. "There's the issue of population that live along the border area. Some of them are migrant cattle herders. It's going to be quite difficult to define citizenship for them, so these are really difficult issues which need to be considered.

"There are lessons historically out of Africa elsewhere. For example when Eritrea become independent from Ethiopia ... some of these issues could be learned from the Eritrea example I think."

Will the referendum lead to a better standard of life for those who live in one of the poorest countries in the world?

If it is created Southern Sudan will be one of the poorest countries in the world despite its oil wealth and will face huge challenges. The charity World Vision says children in Southern Sudan are three times more likely to die than kids in the north, while 90 percent live on less than $1 a day. The future of the oil-rich Abyei area will be decided in a second referendum and the people in the Nuba Mountains and the Blue Nile areas are to have a "popular consultation" on their future.

CNN's Dan Rivers and Mark Bixler contributed to this report.