In 1960, the U.S. Forest Service started keeping detailed records of damage caused by wildfires. ... Between 2000 and 2013, nearly 161 million acres were consumed by wildfires -- more in 13 years than in the previous 40 years, combined. ... they would have been had fuel sources been able to burn off naturally over time.
A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the sun, Earth and moon are aligned (in "syzygy") exactly, or very closely so, with the Earth in the middle.
Seafood Watch has had an immense influence on decisions regarding illegal fishing practices and has helped design sustainable seafood environments due to their lists of seafood that should be eaten without worries.
The hemoglobin molecule has four binding sites for oxygen molecules: the iron atoms in the four heme groups. Thus, each Hb tetramer can bind four oxygen molecules.