Which of the following expressions is used to calculate the change in population size? F. births plus deaths G. births plus deaths plus population H. births minus deaths I. births minus deaths plus population

Which of the following factors is NOT considered when determining a nation's water footprint ? I. The daily per capita use of fresh water, II. The amount of water used to produce exported crops, III. The daily per capita amount of precipitation. (a) I only, (b) II only, (c) III only, (d) I and II, (e) II and III.

Scientists do not all agree on the specific carrying capacity of Earth for humans. Why might this carrying capacity be difficult to determine?

Bleaching events lead to the destruction of what kind of marine ecosystem? F. coastal wetlands G. coral reefs H. mangrove swamps I . salt marshes

Write a short response. Explain the difference between density dependent and density independent deaths in a population.

Viruses are the cause of many infectious diseases, such as common colds, flu, and chickenpox. Viruses can be passed from one person to another in many different ways. Under what conditions do you think viral diseases will spread most rapidly between humans? What can be done to slow the spread of these viruses?

Most ocean pollution arises from activity on land. How does land pollution end up in the oceans?

Atmospheric brown cloud results from a combination of I. primary and secondary pollutants. II. $\mathrm{PM}_{2.5}$ and $\mathrm{O}_{3}$. III. volatile organic compounds and $\mathrm{O}_{3}$. (a) I only, (b) II only, (c) III only, (d) I and II, (e) II and III.

You want to conduct a natural experiment to test whether leakage from a manure lagoon has an adverse effect on a nearby stream. What is an appropriate null hypothesis for your experiment? (a) There will be a higher abundance of an indicator species in the stream before the lagoon began leaking than after it began leaking. (b) There will be a higher evenness of an indicator species in the stream before the lagoon began leaking than after it began leaking. (c) There will be a lower abundance of an indicator species in the stream before the lagoon began leaking than after it began leaking. (d) There will be no difference in the abundance of phytoplankton in the stream before the lagoon began leaking and after it began leaking. (e) There will be no difference in the abundance of an indicator species in the stream before the lagoon began leaking and after it began leaking.

A scientist finds no evidence that any of the species in a particular community are competing and concludes that competition never played a role in the development of this community. Could this conclusion be valid ? Write a paragraph to explain your answer.

Saltwater intrusion is likely to occur when (a) a cone of depression is created near a coastal ecosystem. (b) humans drill into a confined aquifer near the coast. (c) farmers irrigate their crops with an excess of saline water. (d) an artesian well is created near the coast. (e) the soil near a coastline allows for rapid water drainage.

What is the difference between swamps and marshes? F. Marshes attract birds, swamps attract amphibians. G. Marshes are freshwater, swamps are saltwater. H. Marshes contain non-woody plants, swamps contain woody plants. I. Marshes are mostly in the southeast U.S., swamps in the northeast U.S.

Thomas Malthus introduced (a) the study of human demographics. (b) the hypothesis that humans could exceed Earth's carrying capacity. (c) the concept of variation in replacement-level fertility due to differences in industrialization. (d) the age structure diagram. (e) the concept of population momentum.

Why do population sizes not grow indefinitely?