Ice nuclei: A) are particularly abundant in the lower levels ...

[penguins]

Ice nuclei:
 
  A) are particularly abundant in the lower levels of the troposphere.
  B) rarely have six sides.
  C) have a better chance of forming ice at temperatures below -10 degrees Celsius.
  D) begin to serve their function once the temperature falls to 0 degrees Celsius.

Question 2

Heterogeneous nucleation:
 
  A) cannot occur in the presence of hygroscopic particles.
  B) can only occur at humidities in excess of 100 percent.
  C) results in a water droplet that is 100 percent water.
  D) requires condensation nuclei.

[aprice35067]

Answer to Question 1

Answer: C

Answer to Question 2

Answer: D