Anatomical structures, or physiological mechanisms, with no apparent purpose present challenges to evolutionary biologists.

打嗝在解剖结构或者生理机制上并没有显而易见的用途，这使解释它变成了一个对于进化生物学家的挑战。

As the paper says, " The data suggest that a physiological mechanism for increasing salt intake may develop during pregnancy."

正如这篇论文所说，“数据表明，一种增加摄入量的生理机制可能在怀孕期间形成。”

That could suggest a slow-acting physiological mechanism is responsible.

这可能表明一种缓慢作用的生理机制是造成这一现象的原因。

The challenge both companies face, however, is that the physiological mechanisms for long-term pain remain elusive.

然而，两家公司面临的挑战是长期疼痛的生理机制仍然难以捉摸。

He hoped to better understand the physiological mechanisms that affected these four flavors, and his data suggested that sensitivity for each taste did in fact vary across the tongue.

他希望能更好地理解影响这四种味觉的生理机制，而他的数据显示，舌头各部位对每种味道的敏感度确实存在差异。

Your body will jump into this protective physiological, biological mechanism to reduce the amount of energy you're using, which is why it is hard for people to maintain weight.

你的身体会跳入这种保护性的生理、生物机制，以减少你使用的能量，这就是为什么人们很难保持体重的原因。

But their modest efficacy and substantial side effects have spurred the study of alternative physiological mechanisms that could be involved in youth depression and anxiety, so that new therapeutics can be developed.

但它们的功效有限， 副作用很大， 这促使人们研究可能与青少年抑郁症和焦虑症有关的替代生理机制，从而开发出新的疗法。

The logic goes like this then: difference in the size of sex cells leads to differences in typical parental investment, leading to differences in the sorts of psychological and physiological mechanisms that evolved.

逻辑是这样的：性细胞大小的差异导致典型的亲代投资的差异，从而导致进化的心理和生理机制的差异。

In a 2017 review article published by the Oxford University Press, it's been hypothesized that human's natural selection for shorter sleep cycles has compromised the efficacy of the physiological mechanisms that protect against Alzheimer's disease during sleep.

在牛津大学出版社2017年发表的一篇评论文章中，有人假设人类对较短睡眠周期的自然选择已经损害了在睡眠期间预防阿尔茨海默病的生理机制的功效。