自然 しぜん発生 はっせいではありませんでした
shizenhasseidewārimasendeshita

Noun
Desu Copula
no-Adjective

The polite, past negative form of 自然発生

1. Was not spontaneous.; Did not occur naturally.; Was not self-generated.

Past/Perfective
Negative
Polite
Formal Register
Biology