Adapt to the environment, the most fundamental factor is to have a clear cause.

适应环境最根本的因素是要有明确的奋斗目标。

youdao

So you head to a doctor, who may run a test or two. But no clear cause for the symptom shows up.

于是你去看医生，医生也许会给你做一两项检查，但却找不出导致这些症状的原因。

youdao

Objective To evaluate the diagnostic value of DSA in digestive canal bleeding without clear cause.

目的评价数字减影血管造影(DSA)检查不明原因消化道出血的价值。

youdao

But Ban Ki-Moon said Tuesday that the evidence is "quite clear" that humans are the main cause of temperatures rising faster than expected.

VOA: special.2009.12.12

The violence erupted on Friday, but the cause is not clear.

VOA: standard.2010.06.15

Some run in families, but most appear without warning and with no clear cause.

FORBES: Eating Too Much Salt May Trigger MS Or Another Autoimmune Disease

There was also "clear cause for concern" over Iranian nuclear intentions, the MPs said.

BBC: NEWS | UK | Al-Qaeda 'increased threat to UK'

As you say, we have no clear cause and effect indication here.

NPR: High Court Changes Mind on Detainee Appeals