To which substance does ferredoxin transfer an electron? photosystem I
photosystem II
NADP+
NADPH

When analyzing tree rings, what do scientists assume a thin ring indicates?

Why is the theory of evolution important? it disproves all other theories about how life began. it provides a topic for debate. it is a unifying concept in biology. it explains how life began. i know for sure, it is not "it is a unifying concept in biology."

What happens to the average kinetic energy of water molecules as water freezes?