27. In the formation of a root nodule, which step normally occurs first?
(A) Bacteria produce 'nod factors'.
(B) The infection thread is formed.
(C) Plant roots secrete signals that attract Rhizobium.
(D) Vascular connections to the nodule are established.

23. Legumes have long been important in the human diet because they are: (A) Low in fats. (B) Low in carbohydrates. (C) High in fats. (D) High in protein. (E) High in carbodydrates.

24. Upon pathogen attach, plants can defend themselves via following methods EXCEPT _____.(A) Synthesizing chemicals that inhibit the pathogen. (B) Limiting the spread of the pathogen to other cells. (C) Generating antibodies against specific items found in the pathogen. (D) Secreting chemicals that signal the presence of pathogens to other parts of the plant.

25. The innermost layer of the pollen sac wall is the: (A) Sporopollenin layer. (B) Exine. (C) Intine. (D) Sporogenous layer. (E) Tapetum.

26. Self-incompatibility most importantly involves: (A) A biochemical mechanism on the part of the pistil. (B) The genetic identities of pistil and pollen. (C) Morphological difference between flowers. (D) A and B.

28. Which of the following elements is required for the stability of cell walls? (A) Zinc. (B) Chlorine. (C) Calcium. (D) Manganese. (E) Sodium.

29. Which of the following can be sensed by plants? (A) Gravity. (B) Pathogens. (C) Touch. (D) Light. (E) All of above.

30. When oxygen is released as a result of photosynthesis, it is a direct by-product of: (A) Splitting water molecules. (B) Chemiosmosis. (C) The electron transfer system of photosystem I. (D) The electron transfer system of photosystem II.

1. What concentration of magnesium chloride: (MgCl2) in water is needed to produce an aqueous solution having an osmotic pressure of 17.2 atm at a temperature of 27°C? (A) 0.176 M, (B) 0.235 M, (C) 0.353 M, (D) 0.705 M, (E) 1.41 M

2. A general reaction is the formation of molecule C from two reactant molecules, A and B.   A + B → C The reaction was run multiple times at constant temperature using different initial concentrations of the two reactants. The initial rates obtained are included in the table below. The rate equation is of the form: Rate =  Determine the reaction orders with respect to A and B. (A) 1 & 1, (B) 2 & 1, (C) 0 & 1, (D) 0 & 2, (E) 1 & 2

3. Under what conditions does a real gas exhibit nearly ideal behavior?  (A) high temperature and high pressure, (B) high temperature and low pressure, (C) low temperature and high pressure, (D) low temperature and low pressure, (E) it is independent on temperature and pressure