What do you think might have caused hat decrease in carbon dioxide?

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.

i need

which

what is a measurement of the earth’s history divided into time periods?

> fossil record <

sedimentary rock

> geologic time scale <

radioactive elements

i guess because there isn't enough love going around. < 3