Microscopic crystals of silica form a hard rock called chert, ...

[j.rubin]

Microscopic crystals of silica form a hard rock called chert, which can be shaped to form sharp cutting edges.
  Indicate whether the statement is true or false

Question 2

Fossil evidence suggests that such land-dwelling arthropods as _____ had evolved by at least the Devonian.
 A)trilobites
 B)molluscs
 C)scorpions
 D)beetles
 E)spiders

[ergserg]

Answer to Question 1

True

Answer to Question 2

C

[j.rubin]

Excellent

[xiaomengxian]

Thanks for the timely response, appreciate it