So how did the ancient ancestors of starfish go from having bilateral symmetry to having radial symmetry?

那么海星远古祖先是如何从左右对称变成向对称呢？

The evolutionary past of starfishes from bilateral to radial animals is also echoed in their development.

海星从双侧动向动进化历史也反映在它们发展过程中。

Sea cucumbers are members of the phylum Echinodermata, along with sea urchins, starfish and other radially symmetrical, " spiny-skinned" marine invertebrates.

海参是棘皮动门成员，还有海胆、海星和其他向对称“多刺”海洋无脊椎动。

At 4: 29 pm on Tuesday, some six and a half hours after launch, the Shenzhou-16 spacecraft docked with the Tianhe core module's radial port, announced the CMSA.

中国航天局宣布，周二下午4点29分，发射约6个半小时后，神舟16号飞船与天河核向端口对接。

Unlike the Grand Canyon, it wasn't carved by water; it may have formed when the Tharsis bulge rose up, creating the valley as a radial crack in the surface.

与大峡谷不同，它不是由水流蚀刻而成；水手谷可能是在塔尔西斯隆起升起时，在火星表面形成向裂痕。

Radial gates control how much water is released and massive  concrete blocks at the bottom of the chute, called dentates, disperse the flow to reduce erosion as  it crashes into the Feather River.

向闸门控制释放水量，滑槽底部巨大混凝土块（称为齿状）可以分散水流，以减少水流流入羽毛河时侵蚀。

The facility consists of an earthen embankment which forms  the dam itself, a hydropower generation plant that can be reversed to create pumped storage, a service spillway with 8 radial floodgates, and an emergency overflow spillway.

该设施包括形成大坝本身土堤、可反转以形成抽水蓄能水力发电厂、带有 8 个向闸门服务溢洪道以及紧急溢流溢洪道。