The findings (S) place (V) cooking (O) as ~ ※place O as ~「…を~として位置づける」
as a leading reason for 「~の主たる理由として」
why early humans were motivated to control fire in the first place
「なぜ~かということ」
alongside the benefits of (A) <warmth> and (B) <protection against wild animals>
「AとBの利点に加えて」