2.5 million years ago the first genus Homo evolves.
Most nitrogen fixation is performed by bacteria, but they are biotic, not abiotic. Lightning does have the ability to fix atmospheric nitrogen.
A. During aerobic respiration, cells take in O2 (Oxygen is an input of cellular respiration) and release CO2, H2O and ATP.
Cellular respiration equation (THIS IS VERY USEFUL :) ):
C6H12O6 (Glucose) + O2 (Oxygen) = 6CO2 (Carbon dioxide) + 6H2O (water) + 36-38 ATP (energy)
NOTE: Inputs are the things going in, outputs are the things being produced.
WHY THE OTHER ANSWERS ARE WRONG:
B. Not B because it mentions the process of fermentation which is anaerobic.
C. Not C because insulin has nothing to do with cellular respiration in particular but rather blood glucose level homeostasis
D. Not D because although it is partially 'correct', the actual wording (inhaled /exhaled) is incorrect as H2O is produced not exhaled. ATP energy is also produced.
Adhesion allows for it to be easily attracted to glass