Answer;
C. Poor farming techniques that killed the soil were combined with drought.
Explanation;
-The Dust Bowl was caused by several economic and agricultural factors, including federal land policies, changes in regional weather, farm economics and other cultural factors.
-After the Civil War, a series of federal land acts coaxed pioneers westward by incentivizing farming in the Great Plains.
Average annual precipitation and temperature.
Answer:
Option C
Explanation:
Option
A. 6440 mL/min
B. 4340 mL
C. 3500 mL/min
D. 2940 mL/min
Solution
It is required to find the minute ventilation which is equal to the product of rate of breathing and the total amount of gas being inhaled or exhaled per breathe. Let this minute ventilation be denoted by "
"
Thus,

where TD is the tidal volume and Br is the rate of breathing
Substituting the given values we get

We will now reduce the air held in the conducting zone of respiratory system
Air held per breathe 
Total Air held

Amount of fresh air one can breathe in and out every minute

Hence, Option C is correct
Answer:
The cyclins activate the CDKs, which affect the cell cycle at three important checkpoints: Late in the G1 stage of the cell cycle, triggering the cell to move into the S phase.
Explanation: