A(n) ____________ is a substance composed of identical particles ...

[faduma]

A(n) ____________ is a substance composed of identical particles called ______________ that cannot be broken into
  simpler substances by chemical means. Fill in the blank(s) with the appropriate word(s).

Question 2

Why does sound travel rapidly though the lower well-mixed surface layer?
  a. Temperature and pressure are homogeneous.
  b. Temperature and salinity are homogeneous.
  c. High refraction areas are produced.
  d. Density is heterogeneous.
  e. Shadow zones are produced

[isabelt_18]

Answer to Question 1

element; atoms

Answer to Question 2

b

[faduma]

Thanks for the timely response, appreciate it

[xiazhe]

Excellent