. What does it mean that the nitrogen gas needs to be "fixed"?

Nitrogen cycle

Explanation:

Nitrogen fixation is the process by which atmospheric nitrogen is converted by either a natural or an industrial means to a form of nitrogen such as ammonia. In nature, most nitrogen is harvested from the atmosphere by microorganisms to form ammonia, nitrites, and nitrates that can be used by plants.

if you add everything up correctly you should get 69 i got this because 50 plus 19 is it

the alkaline earth metals (beryllium (be), magnesium (mg), calcium (ca), strontium (sr), barium (ba), and radium (ra)) are a group of chemical elements in the s-block of the periodic table with very similar properties: shiny. silvery-white. hopefully this ? i didn't fully understand the question