The scientises are studying the _____ of the animal lifedevelopment可以吗？

The scientises are studying the _____ of the animal lifedevelopment可以吗？
The scientises are studying the _____ of the animal life
development可以吗？

The scientises are studying the _____ of the animal lifedevelopment可以吗？
The scientists are studying the ( details ) of the animal life.
Development 也可以

mystery 玄妙，神秘，奥妙
科学家们在研究动物生命的奥妙。

habitats(栖息地)、process(过程)、reproduction(繁殖)development也可以

总该有些提示吧，或者上下文啊，这样的话答案可多啦

habit

regulation规律