Depression that repeatedly occurs with the onset of autumn and winter is to seasonal affective disorder as chronic, low -grade depression is to dysthymic disorder. Seasonal affective disorder is a type of depression that is related to changes in seasons such that it begins and ends at about the same times every year. Dysthymic disorder is a smoldering mood disturbance characterized by a long duration as well as transient periods of normal blood.
Decent from a common ancestor; natural selection.
Answer:
lungs:
The blood first enters the right atrium.
The blood then flows through the tricuspid valve into the right ventricle.
When the heart beats, the ventricle pushes blood through the pulmonic valve into the pulmonary artery.
The pulmonary artery carries blood to the lungs where it “picks up” oxygen.
It then leaves the lungs to return to the heart through the pulmonary vein.
The blood enters the left atrium.
It drops through the mitral valve into the left ventricle.
The left ventricle then pumps blood through the aortic valve and into the aorta. The aorta is the artery that feeds the rest of the body through a system of blood vessels.
Blood returns to the heart from the body via two large blood vessels called the superior vena cava and the inferior vena cava. This blood carries little oxygen, as it is returning from the body where oxygen was used.
The vena cavas pump blood into the right atrium and the cycle begins all over again.
Answer:
Looking at tibetan highlanders who thrive at high altitudes- normally that would make us sick- they have adapted, 60% oxygen- could pose huge health issue (live with 10% less oxygen in blood than us)
Explanation:
Evolutionary adaptations- involve a change in the genetic makeup to help individuals survive in environment. Tibetans have adaptations to let them function at high altitudes
