自然 しぜん発生 はっせいじゃありませんでした
shizenhasseijārimasendeshita

Noun
Desu Copula
no-Adjective

The polite, past negative form of 自然発生

1. It wasn't natural.; It didn't occur naturally.; It wasn't spontaneous.

Past/Perfective
Negative
Polite
Terminal Form
Biology