<span>Zookeepers
have a difficulty of keeping koala bears alive because Koala bears are
susceptible to viral infections. There is a virus that is present to Koalas
which is called the Koala retrovirus. Koala retrovirus makes a Koala bear more
susceptible to infections and even cancer. </span>
From west to east over the United States.
I think the best phrase to describe this would be Founder effects. Founder effects occurs when a new colony is started by a few members of the original population. This small population size means that the colony may have; a non-random sample of genes in the original population. Reduced variation from the original population.. According to Bottlenecks and founder effects, genetic drift can cause big losses of genetic variation for small populations.
The oxygen that goes through alveoli and diffuses into blood capillaries. The oxygenated blood goes though aorta and is pumped by the heart and goes out through the vena cava to be distributed to the whole body. the deoxygenated blood comes back to the heart from the body and is pumped back towards the lungs. the carbon dioxide diffuses out of the blood capillaries and goes out of the body.