This explosion is only internal forces, and so you can write down...

爆炸属于内力，你可以写下。

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Internal genetic factors were also crucial in the Cambrian explosion.

内部遗传因素是还关键的在寒武纪爆炸。

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Internal genetic factors were also crucial in the Cambrian explosion.

内部遗传因素是还关键的在寒武纪爆炸。

youdao