35. Soil

How did the addition of a gene for citrate synthesis increase the tolerance of tobacco and papaya plants to high aluminum concentrations in the soil?

If a plant's leaves are yellowing, it may be that the plant is deficient in the elements needed to make chlorophyll, one of which is __________.

Which organisms are primarily responsible for breaking down bare rock to form soil?

The particles in soil are important because they __________.

When you add "plant food" to your potted geraniums, what are you actually providing the plant with?

Which of the following best describes soil in many tropical rain forests?

Fertilizers are usually enriched in __________.

Why is humus a beneficial component of soil?

Which of the following is a true statement regarding mineral deficiency symptoms in plants?

Why do farmers need to be concerned with the pH level of soil?

Soil can easily become deficient in __________ because these ions are negatively charged and do not stick to negatively charged soil particles.

The American Dust Bowl of the 1930s resulted from __________.

Phytoremediation is showing promise as a sustainable, cost-effective way to decontaminate soil and water. In the case of a hyperaccumulater such as Thlaspi caerulescens, however, what might be a drawback of the technology?

Which of the following would be considered a sustainable agricultural practice?

A botanist claims to have discovered a new macronutrient required for plant growth. Most of this scientist's colleagues are skeptical of her claim. Why might they consider it unlikely?