What is photoperiodisom?

Is there a Bible verse that references gravity? Which direction do planets orbit the sun? What does Leda mean? Is oxygen part of the atmosphere? What does Sagastume mean? What is the shape of the earths shawdow on the moon during a lunar eclipise? What is a light up frisbee? What do you call someone who studies astronautics? Why does Ender practice with his original launch group? What are some tools used to predict tornadoes? What color is the phoenix constellation? Does the sun move counter clockwise in the southern hemisphere? What is the resolution of the story alunsina and tungkung langit? What can Zeus shape shift into? What is a form of water falling from the sky and what is it measured with? What is revealed by the red color of the super giant star called Betelgeuse? Was the moon a crater? How was Dawlish Warren formed? What was the scientist Henrietta leavitt famous for? What is the most prominent feature in jupiters surface?