HELP! Does hydrogen oxygen have large or small difference of ionization energy? What about for electron affinity?

Ab c or d ? i’m not sure what the answer is

What is a difference between a mixture of elements and a mixture of compounds

Which answer tells the reason the earth’s climate is getting warmer? too many animals are becoming extinct. large glaciers are melting in antarctica. the earth is moving closer to the sun. driving cars gives off gases that trap heat in the atmosphere.