Which type of graph would best illustrate the presence and abundance of nitrogen-fixing bacteria in different soil samples?

• A. A line graph showing soil temperature changes over time
• B. A bar graph showing the number of nitrogen-fixing bacteria in each soil sample
• C. A scatter plot of soil pH versus moisture content
• D. A pie chart showing the percentage of different minerals in the soil

Answer: (B)

Verified step by step guidance

1. Step 1: Identify the variables involved in the problem. Here, we want to illustrate the presence and abundance of nitrogen-fixing bacteria across different soil samples. This means we have categorical data (different soil samples) and numerical data (number of bacteria).
2. Step 2: Understand the purpose of the graph. We want to compare the abundance of bacteria between different soil samples clearly and effectively.
3. Step 3: Evaluate the types of graphs given: a line graph is best for showing changes over time, a scatter plot is good for showing relationships between two continuous variables, and a pie chart is used to show proportions of a whole.
4. Step 4: Recognize that a bar graph is ideal for comparing quantities across different categories, such as the number of nitrogen-fixing bacteria in each soil sample.
5. Step 5: Conclude that a bar graph will best illustrate the presence and abundance of nitrogen-fixing bacteria in different soil samples because it clearly shows differences in bacterial counts across categories.