________% of the food we consume comes from ________ crop species.
90; 15
Factors involved in soil formation are ________.
weathering of parent material, freezing/thawing, tree roots
Which process not only controls erosion, but can also help to replenish soil nutrients?
crop rotation
Industrial agriculture ________.
increased our ability to obtain more food from the same area
Over time, pesticides become less effective. This is because __________.
pests can evolve defenses against pesticides
Leaching ________.
removes water-soluble nutrients from soils
Based on the information in the figure, you decide to make changes in your diet to diminish your ecological footprint (the environmental impact of your food choices) by ________.
shifting your protein intake from beef and pork to eggs and dairy products
Relative to sustainable agriculture, insects’ roles are as ________.
essential pollinators and predators
Swidden agriculture is necessary in rainforests for all of the following reasons EXCEPT __________.
the soil of rainforests is not suitable for forest growth
To make organic fertilizer by composting, you do not include ________.
shredded plastic and metals, waste from animal butchering
All of the following practices are used to control soil erosion EXCEPT __________.
industrial monoculture agriculture
Humus is ________.
composed of organic matter and is necessary to fertility and holding soil moisture
We lose 5 to 7 million ha of productive cropland per year to ________.
erosion, over-irrigation, and overgrazing
Erosion usually begins when __________.
vegetation is removed either naturally or by humans
Of the following, ________ best describes integrated pest management (IPM).
biocontrol measures, crop rotation, and habitat diversification
Seed banks (institutions that store and preserve seeds) are important for ________.
protecting genetic diversity
Monoculture ________.
is an agricultural practice of growing large stands of a single species
In regard to energy efficiency, aquaculture is __________.
incredibly energy-efficient compared to harvesting fish from open waters
During the past half-century, global food production has ________ world population growth.
grown at a faster rate than
Which of the following soil horizons is most severely affected by erosion?
The comparison shown in the figure is environmentally significant because ________.
production of beef and pork is resource-intensive
The O horizon of soils consists of ________.
mostly organic material
The consequences of over-fertilizing include ________.
eutrophication and dead zones in nearby aquatic ecosystems
The Conservation Reserve Program pays farmers to ________.
stop cultivating highly erodible land
The loss of more than 10% productivity in an arid area due to erosion, soil compaction, deforestation or overgrazing is ________.
Terracing, contour farming, intercropping, and crop rotation all ________.
are techniques for conserving soil resources and fertility
We will be able to support more people with the same amount of food supply if most people eat which of the following types of diet?
a vegetarian diet
Desertification of soil __________.
can be caused by overgrazing
The use of biocontrol runs the risk of __________.
the control agent negatively impacting other species besides the species needing to be controlled
Aquaculture ________.
can bring economic benefits and food security to many developing regions
Recombinant DNA ________.
is the merging of DNA from unrelated organisms to create new genetic varieties
Over-irrigation can result in ________.
soil salinization and waterlogging
Green Revolution techniques ________.
have increased crop yields but may not be sustainable
Which of the following are farms that concentrate on raising large numbers of animals of all the same type in a small area?
Researchers have demonstrated that organic farming ________.
decreased organic soil losses while giving yields comparable to conventional farming
Until about 10,000 years ago, our species depended on ________.
hunting and gathering
Monoculture, the practice of planting large areas with a single crop ________.
is a development of industrial agriculture
Bt crops ________.
have been given a bacterial gene that gives chemical protection against pests