Leatherback sea turtle the offspring with any special advantages. While other sea turtle species almost always return to their hatching beach, leatherbacks may choose another beach within the region. They choose beaches with soft sand because their softer shells and plastrons are easily damaged by hard rocks. Nesting beaches also have shallower approach angles from the sea. This is a vulnerability for the turtles because such beaches easily erode. They nest at night when the risk of predation and heat stress is lowest. As leatherback turtles spend the vast majority of their lives in the ocean, their eyes are not well adapted to
Varieties of Chinese their own standard languages. In China, however, Literary Chinese maintained its monopoly on formal writing until the start of the 20th century. The logographic writing, read with varying local pronunciations, continued to serve as a source of vocabulary and idioms for the local varieties. The new national standard, Vernacular Chinese, the written counterpart of spoken Standard Chinese, is also used as a literary form by speakers of all varieties. Dialectologist Jerry Norman estimated that there are hundreds of mutually unintelligible varieties of Chinese. These varieties form a dialect continuum, in which differences in speech generally become more pronounced as distances