Which "sphere" is not directly studied in one of the main branches of earth/space science (geology, astronomy, meteorology, or oceanography)?

The carbon cycle is best defined as a process in which a. carbon changes from inorganic forms to organic forms and back b. carbon is changed into other elements such as oxygen or nitrogen c. carbon is continually created from the sun’s energy by plants d. carbon is consumed and regenerated from other elements such as oxygen and nitrogen

What happens when two nitrogen atoms share electrons

What did nikola tesla invent that influence our way of living?