Question

to understand one possible reason why the volume has changed, look at how the population has changed.
the first graph below shows how the u.s. population changed from 1950 to 2005. the second graph shows the volume of groundwater and all other fresh water withdrawn during the same time period.
u.s. population size

volume of fresh water withdrawn per year in the u.s.

data source: united states geological survey
select the statement that is supported by the data.
between 1950 and 1980, the volume of fresh water withdrawn approximately doubled. this volume of fresh water supported a population that also increased.
between 1950 and 1980, the u.s. population and the volume of fresh water withdrawn increased. but the volume of fresh water withdrawn increased by a smaller factor than the population did.

Explanation:

To solve this, we analyze the two graphs:

Analyzing Population (1950 - 1980):

• In 1950, the U.S. population is ~150 million.
• In 1980, the population is ~250 million.
• Factor of increase: $\frac{250}{150} \approx 1.67$ (less than doubling).

Analyzing Fresh Water Withdrawal (1950 - 1980):

• In 1950, the total fresh water (groundwater + other) is ~250 $km^3$.
• In 1980, the total fresh water is ~500 $km^3$.
• Factor of increase: $\frac{500}{250} = 2$ (doubled).

Evaluating the Statements:

1. First Statement:

• “Between 1950 and 1980, the volume of fresh water withdrawn approximately doubled.” (True: 250 → 500 $km^3$ is a doubling.)
• “This volume of fresh water supported a population that also increased.” (True: Population rose from ~150M to ~250M.)

1. Second Statement:

• “the volume of fresh water withdrawn increased by a smaller factor than the population did.” (False: Water withdrawal increased by a factor of 2; population increased by ~1.67. So water withdrawal’s factor is larger, not smaller.)

The first statement is supported: fresh water withdrawal doubled (250 to 500 $km^3$) between 1950–1980, and the population (150M to 250M) also increased during this period. The second statement is false because the water withdrawal’s increase factor (2) was larger than the population’s increase factor (~1.67).

Answer:

Between 1950 and 1980, the volume of fresh water withdrawn approximately doubled. This volume of fresh water supported a population that also increased.