The Reality Reports

A Planet With A Long Memory: Earth is about 4.5 billion years old, and life has existed on it for more than 3.5 billion years. During that time, countless species have appeared, evolved, and disappeared. Scientists estimate that more than 99.9% of all species that ever lived on Earth are now extinct. This means nearly all forms of life that once existed no longer survive today.

Introduction To Blood And Oxygen Transport: Blood is essential for carrying oxygen throughout the body, but not all creatures use the same system. Humans and most animals rely on hemoglobin, an iron-based protein that turns blood red when it binds with oxygen.  However, some creatures have taken a different evolutionary path, using hemocyanin, a copper-based molecule, that gives their blood a distinct blue color.