A 44-year-old Swedish man, Peter Skyllberg, was found in a car buried under snow, at the end of a forest track more than 1 km from a main road in northern Sweden. He survived for two months without food by eating handfuls of snow. But how long can people go without food? Skyllberg had been inside the car since 19 December, 2011. Experts believe it's possible for the human body to survive without food for up to two months. Last year, a 56-year-old woman from British Columbia survived nearly 50 days in the Nevada wilderness on sweets and water after being stranded in the mountains while her husband went in search of help. In fact there're many causes that can influence a person's ability to survive, such as the way the body's metabolism  slows down to keep energy. When the body stops getting food, it has to live on the stored sugars. When this runs out, fat is then turned into the second energy supply. After the fat runs out, the body must take recycled protein from the system and finally from the muscles. But this is very expensive fuel for the body. It's like being in a cold house and burning furniture instead of firewood. However, the muscle loss slows the body's work, causing it to burn calories at a slower rate. Being trapped into a small space would have helped Skyllberg keep precious calories. The car was covered in snow, creating what some experts have described as an "igloo effect" on the car. A person's mental state can play a key role in how long they survive, according to Stephen Joseph, a professor at the University of Nottingham. "In dangerous situations survival depends on personalities. Some might lose hope, while others are more hopeful." says Joseph. "Hope is probably a big key to this." What may partly lead to Peter Skyllberg's survival of two months according to the text?
Enough food. Fast metabolism. Low temperature. High spirits.
Question: A 44-year-old Swedish man, Peter Skyllberg, was found in a car buried under snow, at the end of a forest track more than 1 km from a main road in northern Sweden. He survived for two months without food by eating handfuls of snow. But how long can people go without food? Skyllberg had been inside the car since 19 December, 2011. Experts believe it's possible for the human body to survive without food for up to two months. Last year, a 56-year-old woman from British Columbia survived nearly 50 days in the Nevada wilderness on sweets and water after being stranded in the mountains while her husband went in search of help. In fact there're many causes that can influence a person's ability to survive, such as the way the body's metabolism  slows down to keep energy. When the body stops getting food, it has to live on the stored sugars. When this runs out, fat is then turned into the second energy supply. After the fat runs out, the body must take recycled protein from the system and finally from the muscles. But this is very expensive fuel for the body. It's like being in a cold house and burning furniture instead of firewood. However, the muscle loss slows the body's work, causing it to burn calories at a slower rate. Being trapped into a small space would have helped Skyllberg keep precious calories. The car was covered in snow, creating what some experts have described as an "igloo effect" on the car. A person's mental state can play a key role in how long they survive, according to Stephen Joseph, a professor at the University of Nottingham. "In dangerous situations survival depends on personalities. Some might lose hope, while others are more hopeful." says Joseph. "Hope is probably a big key to this." What may partly lead to Peter Skyllberg's survival of two months according to the text?
A. Enough food.
B. Fast metabolism.
C. Low temperature.
D. High spirits.
Answer: