The koala  is possibly one of the best known Australian animals, and is found in four states: Queensland, New South Wales, Victoria and South Australia. The word "koala" comes from an Australian aboriginal word meaning "no drink". Sometimes people call them "koala bears" but koala is not a bear. It belongs to a special group of Australian mammals, called marsupial . Female marsupials have a _ where the baby animals live after they are born. Koalas have soft, thick, grey or brown fur on their backs. The fur on the stomach is white. Koala that live in the south have thicker fur than those in the north because of the cold winters, whereas the koalas in the northern part of the country live in warm to hot weather most of the year so have thinner fur. A koala has a large hairless nose and round ears. Koalas don't have tails. Adult koalas measure between 7 and 14 kilograms. Koalas spend nearly all their time in the trees using their sharp, curved claws and long toes to climb about and to hold on to the tree branches. They sleep most of the day, and feed and move from tree to tree mainly at night. The reason koala sleep for much of the day is because their food eucalyptus  leaves are very tough so they use a lot of energy to digest. Sleeping saves energy. Eucalyptus leaves are poisonous to almost every other animal. Koalas rarely drink water; they get water from the leaves they eat. Each koala has a home range made up of several trees that they visit regularly. They normally do not visit another koala's home trees except that a male is looking for a female to mate with. Why do koalas sleep much in the day?
Their foods are poisonous They want to save energy for the activities at night They can't get enough energy from their tough foods They can't get enough water from their leaves
Question: The koala  is possibly one of the best known Australian animals, and is found in four states: Queensland, New South Wales, Victoria and South Australia. The word "koala" comes from an Australian aboriginal word meaning "no drink". Sometimes people call them "koala bears" but koala is not a bear. It belongs to a special group of Australian mammals, called marsupial . Female marsupials have a _ where the baby animals live after they are born. Koalas have soft, thick, grey or brown fur on their backs. The fur on the stomach is white. Koala that live in the south have thicker fur than those in the north because of the cold winters, whereas the koalas in the northern part of the country live in warm to hot weather most of the year so have thinner fur. A koala has a large hairless nose and round ears. Koalas don't have tails. Adult koalas measure between 7 and 14 kilograms. Koalas spend nearly all their time in the trees using their sharp, curved claws and long toes to climb about and to hold on to the tree branches. They sleep most of the day, and feed and move from tree to tree mainly at night. The reason koala sleep for much of the day is because their food eucalyptus  leaves are very tough so they use a lot of energy to digest. Sleeping saves energy. Eucalyptus leaves are poisonous to almost every other animal. Koalas rarely drink water; they get water from the leaves they eat. Each koala has a home range made up of several trees that they visit regularly. They normally do not visit another koala's home trees except that a male is looking for a female to mate with. Why do koalas sleep much in the day?
A. Their foods are poisonous
B. They want to save energy for the activities at night
C. They can't get enough energy from their tough foods
D. They can't get enough water from their leaves
Answer: