Answer:
all of the above (d) is right
Debido a que el hidrógeno molecular expulsado por los volcanes se difundió en el espacio, la Tierra ganó una atmósfera rica en oxígeno. Otra posibilidad es que el oxígeno se acumule debido a una disminución de gases – como el hidrógeno – que reaccionan con y por lo tanto "absorben" el oxígeno.
Explanation:

<h2>Fixation</h2>
Nitrogen in its gaseous form (N2) can’t be used by most living things. It has to be converted or ‘fixed’ to a more usable form through a process called fixation. There are three ways nitrogen can be fixed to be useful for living things:
<h3>Biologically: </h3>
Nitrogen gas (N2) diffuses into the soil from the atmosphere, and species of bacteria convert this nitrogen to ammonium ions (NH4+), which can be used by plants. Legumes (such as clover and lupins) are often grown by farmers because they have nodules on their roots that contain nitrogen-fixing bacteria.
<h3>Through lightning: </h3>
Lightning converts atmospheric nitrogen into ammonia and nitrate (NO3) that enter soil with rainfall.

Answer:
<em><u>A</u></em><em><u>:</u></em><em><u> </u></em><em><u>crust</u></em>
<em><u>B</u></em><em><u>:</u></em><em><u> </u></em><em><u>mantle</u></em><em><u> </u></em>
<em><u>C</u></em><em><u>:</u></em><em><u>core</u></em><em><u> </u></em><em><u>explanation</u></em><em><u> </u></em><em><u> </u></em><em><u>may</u></em><em><u> </u></em><em><u>it</u></em><em><u> </u></em><em><u>help</u></em><em><u> </u></em><em><u>u</u></em><em><u> </u></em><em><u>buddy</u></em><em><u> </u></em>
Answer:
There would be increase in carbon dioxide in the atmosphere
Explanation:
Without the thousands of trees to hold the carbon dioxide and turn it back to oxygen, the CO2 is rather just sitting there in the atmosphere.