The answers A
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Answer:
a series of mitochondrial proteins that transport electrons of hydrogen, released in the Krebs cycle, from acetyl coenzyme A to inhaled oxygen to form H2O: the energy released in the process is conserved as ATP.
Explanation:
Because some plants can be some type of medicines and we need those. Also some animals use it to keep them alive and if that plant becomes extinct so can the animal then ruin how our ecosytem runs.