How did harry potter survive when voldemort killed him?

well that depends on which time you are asking about. if you are talking about when he was a baby then it was the fact that his mother never moved from infront of him protecting him, thus her love was stronger that voldemort

but if you are talking about when he was in the forest in the 7th book then its because several reasons.

1. he went to the forest to protect the ones he loved

2. voldemort didnt kill harry, he killed the part of his own soul that was inside of harry.

3. Voldemort was using the elder wand to kill harry but the wand belonged to harry besause draco beat dumbledore, and harry beat draco. so the wand belongs to harry. and the wand being smart wouldnt kill or harm its master (which is why the curciatas curse wouldnt work after the kings cross scene)

4. because harry was the master of death. the invisibality cloak, the ressuraction stone and the elder wand all belonged to him

5. cause hes Harry Freaking Potter!

c. in the address bar

the krebs cycle and electron transport occur in the mitochondria, though other than that i would need to know more information.