Analysis of the Stone Artifacts from Zhoukoudian Indicate That the Tools

Analysis of the stone artifacts from Zhoukoudian indicate that the tools from

A) the later stages are large and crudely made.
B) the earliest stages are made from flint and fine-grained quartz.
C) all stages are identical to each other.
D) the later stages are heavier and larger than the previous stage.
E) the later stages are small and the tool materials are of better quality than the previous stages.