The diagram illustrates how the cutting tools in the Stone Age were developed.
Overall, the stone-carved 0. 8 million years ago became more refined and appropriate for cutting.
Tool A was made approximately 1. 4 million years ago. It was like an animal tooth about 9 cm long with a rough surface. The front part of the cutting tool was quite broad, and its top edge was smaller than the bottom. From the side, it was just as narrow as a stick. Moreover, the back part was flatter than the front area.
Tool B was used about 0. 8 million years ago. Although both of the two tools were made of stone, tool B was advanced than the previous one. It was about 12 cm in length. Its front part became smoother with more cuts, which made it look like a diamond. Observed from the side, it had quite an acute top, being very useful for cutting. The back shows that tool B was narrower to the top and extensively more detailed than tool A.
The diagram illustrates how the cutting
tools
in the Stone Age
were developed
.
Overall
, the stone-carved 0. 8 million years ago became more refined and appropriate for cutting.
Tool A
was made
approximately 1. 4 million years ago. It was like an animal tooth about 9 cm long with a rough surface. The front part of the cutting
tool
was quite broad, and its top edge was smaller than the bottom. From the side, it was
just
as narrow as a stick.
Moreover
, the back part was flatter than the front area.
Tool B was
used
about 0. 8 million years ago. Although both of the two
tools
were made
of stone,
tool
B
was advanced
than the previous one. It was about 12 cm in length. Its front part became smoother with more
cuts
, which made it look like a diamond. Observed from the side, it had quite an acute top, being
very
useful for cutting. The back
shows
that
tool
B was narrower to the top and
extensively
more detailed than
tool
A.