に[応「おう」]じて(は)/に[応「おう」]じ(た) => In response/reply to A, In line with A; That fits with A N2
Based, Focused, Depending on
[一方「いっぽう」]だ => Change A continues, A does not stop N2
Miscellaneous
[一方「いっぽう」] => On one hand A, on the other, B; Although A, at the same time, B N2
Contrast,Surprise