Study Guide

Field 068: Agriculture

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Sample Selected-Response Questions

Competency 0001
Foundations of Agricultural Education

1. The Smith-Hughes Act of 1917 created federal support for establishing which of the following?

  1. land-grant colleges for teaching agriculture
  2. high school vocational agriculture programs
  3. the Cooperative Extension System
  4. experiment stations for conducting research
Answer
Correct Response: B. This question requires examinees to demonstrate an understanding of major historical developments in agriculture, career and technical education, and FFA. The Smith-Hughes Act of 1917 provided federal funds for the training of students in the trades, including agriculture and home economics. This and other requirements resulted in the creation of distinct vocational high school programs that required that at least 50% of students' time be spent on job-related learning.

Competency 0002
Agricultural Business

2. Use the graph below to answer the question that follows.

The graph above shows the supply and demand curves for apples grown in New York State. If all other market conditions remain constant, which of the following is most likely to cause Curve 2 to shift to the left by the greatest amount?

  1. the use of more efficient orchard management systems
  2. an increase in the number of trees planted per acre
  3. a long dry spell in the middle of the growing season
  4. the development of new apple varieties and rootstocks
Answer
Correct Response: C. This question requires examinees to demonstrate knowledge of economic principles and concepts, such as supply and demand, and their application to agricultural enterprises. In the graph shown above, Curve 2 represents the supply of apples, since as the price of apples increases, apple growers will boost production to increase the quantity of apples on the market. The equilibrium price of apples is represented by the intersection of the two curves. If Curve 2 shifts to the left, then the equilibrium price will move upwards along Curve 1. This implies that the supply of apples has decreased and the equilibrium price has increased. A long dry spell in the middle of the growing season will cause a reduction in the supply of apples and an increase in equilibrium price.

Competency 0003
Animal Science

3. Prostaglandin F2 alpha can be used to synchronize estrus in a herd of beef cattle. This substance synchronizes estrus by stimulating the

  1. regression of the corpus luteum
  2. release of an oocyte from the mature follicle
  3. thickening of the uterine lining
  4. secretion of large amounts of luteinizing hormone
Answer
Correct Response: A. This question requires examinees to demonstrate knowledge of animal reproduction and breeding practices. In the normal bovine estrus cycle, the corpus luteum forms from the ruptured follicle after ovulation. As the corpus luteum matures, it secretes increasing amounts of progesterone and small amounts of estradiol in response to luteinizing hormone (LH). The presence of these hormones induces physiological changes in the uterus associated with the preparation for pregnancy. If pregnancy does not occur, the corpus luteum degenerates and progesterone levels fall. This drop in progesterone levels stimulates a rise in follicle-stimulating hormone (FSH) and LH levels and a new cycle begins. When prostaglandin F2 alpha is administered during the luteal phase, it stimulates the degeneration of the corpus luteum and levels of circulating progesterone decrease. These changes initiate the onset of a new cycle in treated cows. Herd managers use this method to synchronize the estrus cycles of cows in a herd so that they can better regulate breeding activities.

Competency 0004
Plant Science

4. The Asian long-horned beetle is an invasive species that was found bored into wooden crates that were shipped to New York. The beetles have no natural enemies in New York. Which strategy is likely to be most effective in slowing the spread of this invasive pest?

  1. power washing vehicles that have visited infested areas
  2. applying adhesive traps around the trunks of mature hardwood trees
  3. encouraging campers and others to obtain their firewood locally
  4. spraying hardwood trees with insecticides each spring
Answer
Correct Response: C. This question requires examinees to demonstrate knowledge of major plant diseases and pests and methods for their prevention and control. The Asian long-horned beetle was introduced accidently into the United States from wooden shipping crates. The beetle attacks a wide variety of hardwood trees, such as maple and poplar. To date, the best methods of control are prevention and quarantining. This involves implementing steps to ensure that infected wood is not transported into non-infested areas. One such step is to encourage campers and others to obtain their firewood locally, rather than moving wood from potentially infested areas into non-infested areas.

Competency 0005
Food Systems, Science, and Safety

5. Which of the following best describes the reason agricultural produce samples are often tested for coliform bacteria?

  1. All coliform bacteria are pathogenic to humans and represent a significant health threat.
  2. The presence of coliform bacteria is a sign that the produce is old and approaching a state of being spoiled.
  3. High levels of coliform bacteria indicate that the produce is in a diseased state and is unsellable.
  4. The presence of coliform bacteria indicates that pathogenic strains of bacteria may be present on the produce.
Answer
Correct Response: D. This question requires examinees to demonstrate an understanding of contaminants that can affect food safety. Coliform is a family of bacteria that typically originate in the intestinal tract of warm-blooded animals. While not all coliform bacteria are pathogenic, the presence of coliform bacteria in food products is a strong indicator that more dangerous microbes may be present in the food due to unsanitary conditions or poor food-handling procedures. Sampling produce for coliform is an effective technique for determining whether the food may harbor microbes that could cause food poisoning.

Competency 0006
Genetics and Biotechnology

6. In garden peas, the dominant alleles for pod color and seed shape are green and round. The recessive alleles for these traits are yellow and wrinkled. If two pea plants that are heterozygous for both pod color and seed shape are crossed, what proportion of the offspring plants will have green pods and wrinkled seeds?

  1. 1 over 16

  2. 3 over 16

  3. 5 over 16

  4. 9 over 16
Answer
Correct Response: B. This question requires examinees to demonstrate an understanding of the principles of Mendelian genetics and inheritance and the application of those principles to genotype and phenotype variation in plants. The parent plants in this cross are heterozygous for two traits, which means they each contain a dominant allele and a recessive allele for pod color (Gg) and a dominant allele and a recessive allele for seed shape (Rr), with G and R representing the dominant alleles of each gene. A cross between these two plants can be represented as GgRr × GgRr. According to the principle of independent assortment, each parent plant will produce four types of gametes: GR, Gr, gR, and gr. A Punnett square can be used to determine the number and type of genotypes produced by this cross. When a 4 × 4 Punnett square is constructed by placing one set of gametes on the top of the square and the other set of gametes along the side of the square, the results show a total of 16 possible genotypes. For an offspring plant to have a green pod and wrinkled seed phenotype, its genotype must include at least one dominant allele for pod color (GG or Gg) and two recessive alleles for seed shape (rr). The results of the Punnett square show that out of 16 possible genotypes resulting from this cross, three genotypes lead to the specified phenotype (3 over 16).

Competency 0007
Agricultural Technology and Mechanics

7. Use the diagram below to answer the question that follows.

In a hydraulic system, piston 1 has a radius of 8 in and piston 2 has a radius of 16 in. What downward force (F1) must be applied to piston 1 in order to produce an upward force (F2) of 2000 lbs in piston 2? (The formula for the area of a circle is A = πr2.)

  1. 500 lbs
  2. 1000 lbs
  3. 4000 lbs
  4. 8000 lbs
Answer
Correct Response: A. This question requires examinees to apply technological and mechanical principles in agriculture. Because the two pistons are in the same hydraulic system, the system's mechanical properties are governed by Pascal's law, which states that the pressure of the fluid is transmitted equally in all directions. From Pascal's law it follows that pressure on the two pistons must be equal; the pressure on piston 1 equals the pressure on piston 2. Since pressure is force (F) divided by area (A), the following equation is true: F1 over A1 equals F2 over A2. The question asks for the downward force, F1. Solving the equation for F1 and using the given values results in the following:

 F_1=  ((F_2)(A_1))/A_2 =   ((2000 lb)(pi)[(8 in)]^(2 ))/((pi) [(16 in)]^2 )=  (2000 lb)/4 500 lbs

Competency 0008
Environmental Science and Natural Resource Management

8. Controlled grazing by livestock is one approach being used to control unwanted vegetation and protect native plant species in New York State. Which piece of information would likely be most helpful in determining a successful grazing protocol to control unwanted target plants at a particular site?

  1. the mode of seed dispersal used by the target plants
  2. the minimum amount of water needed for regrowth of the target plants
  3. the nutritional values of both target plants and non-target plants
  4. the palatability of the target plants to different livestock
Answer
Correct Response: D. This question requires examinees to apply an understanding of sustainable agricultural practices. One method for controlling unwanted plants, such as invasive species, is to use livestock to consume the undesired plants. Since different livestock have different feeding habits, it is essential to know which livestock (e.g., cattle, goats, sheep) are likely to eat the undesired plants. This technique for controlling weeds is often called prescriptive grazing.