MF RC522的工作频率是（）。

A、耐穿

B、防风

C、透气

D、防雨

A、计算结构平衡

B、保证构件强度

C、保证构件刚度

D、保证构件稳定性

A、机（梭）织粘合衬

B、聚酰胺粘合衬

C、聚乙烯粘合衬

D、聚酯粘合衬

Sea turtles migrate across thousands of miles of ocean before returning to nest on the same stretch of coastline where they hatched, but how they do this has mystified scientists for more than fifty years. Sea turtles likely go to great lengths to find the places where they began life because successful nesting requires a combination of environmental features that are rare: soft sand, the right temperature, few predators, and an easily accessible beach. From this passage it is safe to conclude that sea turtles

A、are not easily observed by scientists.

B、cannot lay their eggs on any beach other than the one on which they hatched.

C、will not lay their eggs on beaches with pebbly sand.

D、must have the ability to precisely detect their location.