1. what is true about relative humidity?

a. it indicates how near the air is to saturation

b. it indicates the actual quantity of water vapor in the air

c. is is the general term used to describe the amount of water vapor in the air

d. it is the temperature to which a parcel of air would need to be cooled to reach saturation

2. what is the dry adiabatic rate?

a. 3.0*c/100 meters

b. 1*c/100 meters

c. 5.0*c/1,000 meters

d. 0.5*c/1,000 meters

3. weather-producing fronts are parts of storm systems called

a. middle-latitude cyclones

b. hurricanes

c. tropical storms

d. tornadoes

4. cool air acts as a barrier over which warmer, less dense air rises, in a process known as

a. divergence

b. frontal wedging

c. orographic lifting

d. subduction

5. which of the following is an example of condensation nuclei?

a. dust

b. smoke

c. salt particles

d. all of the above

6. which cloud type is confined to the middle height range?

a. cirrostratus

b. cumulonimbus

c. altostratus

d. cirrus

7. which of the following processes can produce either rain or snow?

a. the bergeron process

b. the collision-coalescence process

c. both the bergeron process and the collision-coalescence process

d. none of the above

8. which type of precipitation consists of small clear-to-translucent ice particles?

a. rime

b. sleet

c. hail

d. glaze

Our planet has experienced five major extinctions in the four billion year history of life. the first, 450 million years ago, occurred shortly after the evolution of the first land-based plants and 100 million years after the cambrian explosion. the second extinction occurred 350 million years ago, causing the formation of coal forests. next earth experienced two mass extinctions during the triassic period, between 250 and 200 million years ago. the fifth mass extinction occurred 65 million years ago, ending the reptilian dominance of the earth. according to richard leakey, the sixth mass extinction is happening right now. leakey suggests that we, the human race, are the cause. each year, at our hand, approximately 50,000 species vanish from earth. he believes that man is destroying earth at a rate comparable with the impact of a giant asteroid. leakey's statistics indicate that 50% of earth's species will become extinct within the next 100 years assuming leakey's hypothesis of a sixth mass extinction to be true, how will we expect the model to change? a) a sharp spike in the graph approximately 100 million years from now b) a dip in the graph, followed by a sharp spike about 100 million years from now c) a sharp spike in the graph immediately following the "0" location of the x axis d) a plateau following the "0" mark on the x axis, followed by a gradual rise to a new peak