The bottom layer has no dependency on the upper layers due to a loose-coupling design.

由于采用松散耦合的设计，下面的层并不依赖于上面的层。

youdao

Neurons in the upper layers of the superior colliculus have well-defined receptive fields.

神经元在上丘的上层有明确的接收区。

youdao

So these animals have to travel from the ocean's depths toward its upper layers to feast on the phytoplankton growing there.

所以，一些动物为了享受长在最上层的浮游植物，他们会从海洋的深处一直朝着最上层艰苦跋涉。

youdao

The upper layers of a well-designed securitisation vehicle should be all but impervious to loss.

ECONOMIST: Securitisation

That would have made the Atlantic's upper layers less dense, so less liable to sink.

ECONOMIST: The science

The largest earthquakes in the world occur close to plate margins, areas of the Earth's upper layers that are being rammed together or pulled apart.

BBC: Q&A: UK's small-scale earthquakes