Question

paramecium contractile vacuole contractions
salt concentration outside paramecium\tcontractions per minute
very high\t2
high\t8
medium\t15
low\t22
very low\t30
if this data is shown in a bar graph, which description accurately represents the bars?
the graph has five bars of equal height.
the bars range from tallest for very high concentration to shortest for very low concentration.
the bar for very low concentration is twice the height of the bar for medium concentration.
the bar for very high concentration is five times the height of the bar for very low concentration.

Explanation:

Step1: Analyze the data

The contractions per minute values are 2 (very high salt - concentration), 8 (high), 15 (medium), 22 (low), 30 (very low).

Step2: Check each option

• Option 1: The values are different, so bars are not of equal height.
• Option 2: The values are highest for very low and lowest for very high, so this is incorrect.
• Option 3: The value for very low (30) is \( \frac{30}{15}=2 \) times the value for medium (15). So the bar for very low concentration is twice the height of the bar for medium concentration.
• Option 4: The value for very high (2) is \( \frac{2}{30}=\frac{1}{15} \) of the value for very low, not five - times.

Answer:

The bar for very low concentration is twice the height of the bar for medium concentration.