Chapter 32

Plants require the smallest amount of which of the following nutrients? a. oxygen b. phosphorus c. carbon d. iron

Which of the following activities of soil bacteria does not contribute to creating usable nitrogen supplies for plant use? a. the fixation of atmospheric nitrogen b. the conversion of ammonium ions to nitrate ions c. the decomposition of dead animals d. the assembly of amino acids into proteins

By trapping insects, carnivorous plants obtain ________, which they need _______. (Choose the best answer.) a. water... because they live in dry soil b. nitrogen ... to make sugar c. phosphorus... to make protein d. nitrogen ... to make protein

Explain how guard cells limit water loss from a plant on a hot, dry dav. How can this be harmful to the plant?

Certain types of fungi cause diseases in plants. There are a variety of antifungal sprays that can be used to control this problem. Some gardeners constantly spray their plants with fungicides, even when no signs of disease are evident. How might this be disadvantageous to the plant?

If the apples you buy are labeled "organic," does that tell you anything about how they were grown? About the nutritional content of the apples?

Acid rain contains an excess of hydrogen ions \(\left(\mathrm{H}^{+}\right) .\) One effect of acid rain is to deplete the soil of plant nutrients such as calcium \(\left(\mathrm{Ca}^{2+}\right),\) potassium \(\left(\mathrm{K}^{+}\right),\) and magnesium \(\left(\mathrm{Mg}^{2+}\right) .\) Offer a hypothesis to explain why acid rain washes these nutrients from the soil. How might you test your hypothesis?

Agriculture is by far the biggest user of water in arid western states, including Colorado, Arizona, and California. The populations of these states are growing, and there is an ongoing conflict between cities and farm regions over water. To ensure water supplies for urban growth, cities are purchasing water rights from farmers. This is often the least expensive way for a city to obtain more water, and some farmers can make more money selling water than growing crops. Discuss the possible consequences of this trend. Is this the best way to allocate water for all concerned? Why or why not?