Nutrient runoff from a farm causes an algal bloom in a nearby pond. The density of algal cells increases from 1,200 cells/mL on Day 1 to 96,000 cells/mL on Day 5. What is the average rate of change in algal cell density per day during this period?

A researcher measures mercury concentrations in a marine food web affected by industrial pollution. Phytoplankton contain 0.05 ppm of mercury, while sharks at the top of the food chain contain 32.0 ppm. How many times greater is the mercury concentration in the sharks compared to the phytoplankton?

Deforestation for agriculture reduced a tropical forest fragment from 800 hectares in 1990 to 320 hectares in 2020. What is the percent change in the area of the forest fragment over this 30-year period?

Atmospheric data indicates that CO2 levels increased from 350 ppm in 1980 to 410 ppm in 2020 due to human activities. What is the average annual rate of increase in CO2 concentration during this period?

A population of 900 deer lives in an ecosystem with a carrying capacity (K) of 1000. If the maximum per capita growth rate (r_max) is 1.0, calculate the population growth rate (dN/dt) considering density-dependent negative feedback.

A student places 100 isopods in a choice chamber with wet and dry sides to test humidity preference. After 10 minutes, 70 isopods are on the wet side and 30 are on the dry side. Assuming no preference (null hypothesis), the expected count is 50 per side. The critical value for $p=0.05$ with 1 degree of freedom is 3.84. What is the chi-square value and conclusion?

In a phototropism experiment, 200 seedlings are exposed to unidirectional light. Observed results show 140 bending toward light and 60 growing straight. Under the null hypothesis of random growth, expected counts are 100 each. The critical value at $p=0.05$ is 3.84. Which choice correctly describes the statistical outcome?

Researchers test phototaxis in 60 fruit flies, observing 40 move to light and 20 move to darkness. If the null hypothesis states no preference, the expected count is 30 per group. With 1 degree of freedom, the critical value is 3.84. What is the result of the chi-square test?

Ninety fish are released into a tank with equal areas of sand, gravel, and mud. Observed counts are 50 on sand, 30 on gravel, and 10 on mud. The null hypothesis predicts 30 fish per area. The critical value for 2 degrees of freedom at $p=0.05$ is 5.99. What is the chi-square value and biological interpretation?

Fifty caterpillars are offered corn or tomato leaves. Thirty choose corn and 20 choose tomato. The null hypothesis predicts equal preference (25 each). The critical value at $p=0.05$ is 3.84. Which statement correctly reports the chi-square value and conclusion?