Latitudes south of the equator are decipated as numbers

Which experiment would most likely contain experimental bias

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

Which event would lead to primary succession of a forest?