Review the chart, which shows the population sizes of three African animals in 1990 and in 2000.

\begin{tabular}{|c|c|c|}
\hline \multicolumn{3}{|c|}{ Population Estimates of Animals in Africa in 1990 and in 2000 } \\
\hline & 1990 & 2000 \\
\hline Lions & 100,000 & 47,000 \\
\hline Cheetahs & 50,000 & 7,500 \\
\hline \end{tabular}

Which explanation is best supported by the numbers in the chart?

A. Lion and cheetah populations compete for the food source of zebras, and lions outcompete cheetahs.
B. The dwindling zebra population has led to the decline of the predator lion and cheetah populations.
C. Overhunting of lion and cheetah populations has led to a decline in the food source population.
D. Lion and cheetah populations compete for the food source of zebras, and cheetahs outcompete lions.



Answer :

Based on the population estimates provided in the chart for the years 1990 and 2000, let's analyze the data and work toward selecting the best-supported explanation.

The population sizes of Cheetahs and Zebras in 1990 and 2000 are presented below:
- Cheetahs (1990): 100,000
- Cheetahs (2000): 47,000
- Zebras (1990): 50,000
- Zebras (2000): 7,500

### Step-by-Step Analysis:
1. Decline in Cheetah Population:
- Population in 1990: 100,000
- Population in 2000: 47,000
- Decline: \(100,000 - 47,000 = 53,000\)

2. Decline in Zebra Population:
- Population in 1990: 50,000
- Population in 2000: 7,500
- Decline: \(50,000 - 7,500 = 42,500\)

3. Correlation:
- The data shows a significant decline in both cheetah and zebra populations over the decade.
- The decline of cheetahs by 53,000 individuals and zebras by 42,500 individuals suggests a possible link between the reduction in zebras, a primary food source, and the decline in predator populations, such as cheetahs.

### Explanation Supported by Data:
Given the significant parallel decline in both cheetah and zebra populations, the best-supported explanation by the numbers would be:
- The dwindling zebra population has led to the decline of the predator lion and cheetah populations.

This explanation indicates that the reduction in the zebra population, which is a food source for predators like cheetahs (and potentially lions too), has likely contributed to the observed decline in the predator populations due to a decrease in available prey.