Earth's magnetic poles reverse approximately every years? O A. billion
B. 22
C. 10 million
D. 250,000

D. 250,000 years

Explanation:

It's really 200,000 to 300,000 years, but 250,000 years is right in the middle, so it must be 250,000 years.

Hope this helps you! Good luck with your exam/quiz! <3

d.

hope to be marked brainliest

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.