This is a calculation and prediction question requiring you to read values from a graph and determine the change. Figure 2 shows oxygen solubility at 20°C is approximately 9 mg/L and at 40°C is approximately 6 mg/L. The change is 6 - 9 = -3 mg/L (a decrease of 3 mg/L). Since the curve slopes downward (gas solubility decreases with temperature), warming the lake causes oxygen loss. Choice C (decrease by approximately 3 mg/L) is correct. Choices A and B suggest increases, which contradicts the downward-sloping curve. Choice D (decrease by 6 mg/L) would be the change from 9 mg/L to 3 mg/L (from 20°C to 60°C), not to 40°C. Pro tip: For change questions, read both values carefully and subtract to find the difference.

This is a graph interpolation question testing your ability to read values between plotted data points. Figure 1 shows KNO₃ solubility at 40°C is approximately 60 g and at 60°C is approximately 110 g. The question asks for the value at 50°C, which falls exactly between these two temperatures. Since 50°C is the midpoint between 40°C and 60°C, you can estimate the solubility as roughly the midpoint between 60 g and 110 g. The midpoint is (60 + 110) ÷ 2 = 85 g. Choice C (85 g) is correct. Choice A (30 g) is far too low. Choice B (60 g) is the value at 40°C, not 50°C. Choice D (110 g) is the value at 60°C. Pro tip: For interpolation, locate the two surrounding known points and estimate between them.

This is a trend reading question. Following the Mouse curve in Figure 1 from 5°C to 25°C, the metabolic rate starts at approximately 5.5 mL and decreases to approximately 1.5 mL at 25°C. This is a consistent downward trend throughout this temperature range. Choice B (decreases only) is correct. Note that the curve does increase slightly after 25°C (at 35°C it rises to ~2.0), but the question specifically asks about 5°C to 25°C, not the full range. Choice A (increases) is opposite. Choice C (decreases then increases) would be correct for the full 5-35°C range, but not for the 5-25°C range specified. Choice D (constant) is wrong. Pro tip: Read question limits carefully—answer based on the specified range only.

This is a graph reading question. At 2,000 km depth (within the Mantle), trace up to the solid P-wave line. The specification indicates P-waves "increase steadily through the Mantle to ~13 km/s at 2,900 km." At 2,000 km (about 70% through the mantle from 40 to 2,900), the velocity should be around 11-12 km/s. Choice C (12 km/s) is correct. Choice A (7 km/s) is too low. Choice B (10 km/s) is slightly low. Choice D (14 km/s) exceeds the maximum shown. Pro tip: For reading between points, estimate based on the curve's position relative to nearby values.

The bar graph shows mean reaction times for lighting conditions: Bright 210 ms, Dim 260 ms, Red 240 ms, and Blue 225 ms. The lowest bar is Bright at 210 ms, indicating the fastest reaction time. This is correct because shorter bars represent faster times, teaching how to interpret bar graphs for minima. Option A, Dim, has the highest bar and thus the slowest time.

Person P4 averaged the most steps per day according to Figure 1. Comparing the bar heights for all five people (P1–P5), the P4 bar extends highest on the y-axis, indicating the greatest average daily step count during the one-week measurement period.

The towel's mass at 15 min is closest to 125 g. To find this value in Figure 1, locate 15 min on the x-axis and trace up to the curve, then read across to the y-axis. The exponential decay curve shows rapid mass loss initially, and at 15 minutes the mass has decreased to approximately 125 g from its starting value.

The approximate extension when the applied force is 8 N is 3.2 cm. To find this value, locate 8 N on the x-axis of Figure 1, trace up to the data point at that force level, then read across to the y-axis to determine the corresponding extension value. The scatter plot shows a linear relationship, and at 8 N, the extension is approximately 3.2 cm.

The temperature increases overall from 2 to 8 min, but the rate of increase slows after 6 min. Looking at the slope of the line in Figure 1, the temperature rises steeply from 2 to 6 min, then continues to increase but with a gentler slope from 6 to 8 min. This shows that heating continues throughout but becomes less rapid in the later portion of the interval.

Bubble production is highest at approximately 6% sugar concentration according to Figure 1. The curve shows bubble production rate increasing with sugar concentration up to a maximum, then declining at higher concentrations. Following the curve to its peak and reading down to the x-axis shows optimal yeast activity occurs at about 6% sugar.