What is photoperiodisom?

Why is sun give off tremendous amount of energy? Are stars primary sources of light? Can a bat see in total darkness? Which jovian planets do not have internal heat source? Is it ethical for humans to want to populate another planet when it seems they are not looking after the one they have got? What might surface temperatures be like on a planet with no atmosphere? How long do inner planets rotation and revolution around the sun? Do planets and moons shine in the sky due to reflected sunlight? Is Hades stronger than Zeus? How old was john Glenn when he orbited the earth? Does Mars have lava? When is the next lunar eclise and what time? How do counterweights affect launch on trebuchets? The competition between the US and the USSR to put a man on the moon was called the? Which clouds are very high and made ice particles? What plants will be seen as crescent-shaped from the Earth at certain times in its orbit? How was Lhotse Mountain formed? When the star uses up its helium or other elements it collapses into a? What caused the Tuscaloosa tornado? Where is the Roper Mountain Science Center in Greenville South Carolina located?