MSU-GSC ABE REVIEW CENTER

ABE REVIEW CLASS 2021

PRE-BOARD EXAM PART 2

Soil and Water Resources Development and Conservation,

Irrigation, Drainage and allied subjects
By: Engr. Rener B. Tandugon

Exam Guidelines:

1. Exam time at 1-5 pm

2. Participants should turn on camera and follow the prescribed angle. Otherwise, the
examinee will not be included in the ranking.
3. Wear white t-shirt (with print will do). Sleeveless not allowed.
4. On cam participants are allowed only ONCE to request for personal necessity break
during the conduct of the exam.
5. Maximum of 2 minutes only for a personal necessity break.
6. There should be only 3 participants at a time for personal necessity breaks to facilitate
easy monitoring.
7. Please notify the secretariat for the necessity break by sending thru zoom chat privately.
Wait for the reply before exiting for a break.

1. According to Lacey’s theory, the silt factor is

A. Directly proportional to average particle size
B. Inversely proportional to average particle size
C. Directly proportional to square root of average particle size
D. Not related to average particle size
E. None of the above
2. The rainfall rate for successive 10 minute periods within an hour duration storm
has been recorded. If the value of φindex is 3 cm/hour, the runoff will be
A. 2 cm
B. 3 cm
C. 4 cm
D. 5cm
E. None of the above
3. Which of the following is considered as a flexible outlet?
A. Submerged pipe outlet
B. Kennedy’s gauge outlet
C. Gibb’s outlet
 D. All of the above
E. None of the above
4. A crop has a 4 month growing period which is from December up to March of the
next year. Determine the consumptive use of the crop in the month of January if
the pan evaporation for the month is 9.5 cm. Take the consumptive coefficient at
40%, stage growth of the crop as 0.52.
A. 1.6 mm/day
B. 2.5 mm/day
C. 3.4 mm/day
D. 4.3 mm/day
E. None of the above
5. The time required by rainwater to reach the outlet of drainage basin
A. Duration of the rainfall
B. Concentration time of overland flow
C. Time of overland flow
D. Time of concentration
E. None of the above
6. Thirty meters below the static water table, a well reaches. After a full day of 24
hours of pumping at 31.40 L/min, the water level in a test well at 80 m distance is
lowered by half a meter and a well 20 m away, water is lowered at a meter. The
transmissibility of the aquifer of interest is
A. 1.185 m2/min
B. 1.285 m2/min
C. 1.385 m2/min
D. 1.485m2/min
E. None of the above
7. The drainage water intercepting the canal can be disposed of by passing the canal
below the drainage
A. Aqueduct and siphon aqueduct
B. Aqueduct and super passage
C. Super passage and canal siphon
D. Level crossing
E. None of the above
8. The volume of water in the atmosphere is 15,400 km 3. The flow rate of
evaporation from land is 71,500 km3/year and that from the ocean is 565,300
km3/year. Estimate the residence time of water molecules in the atmosphere in
days.
A. 8.8 days
B. 8.2 days
C. 41.3 days
D. 6.5 days
 E. None of the above
9. A hyetograph is a graphical representation of
A. Rainfall intensity and time
B. Rainfall depth and time
C. Discharge and time
D. Cumulative rainfall and time
E. None of the above
10. A small water tank for irrigation has storage of 60 m 3 at the beginning of January.
Compute for the total storage at the end of March if the inflow each month is 4, 6
and 9 respectively, and the outflow is 8, 11 and 5 respectively.
A. 65 m3
B. 36 m3
C. 55 m3
D. 41 m3
E. None of the above
11. Repelling groynes were constructed to repel the water flow away from the banks
and is aligned as,
A. Pointing upstream
B. Pointing downstream
C. Perpendicular to bank
D. Parallel to bank
E. None of the above
12. A system where a long tube is bored deep into the ground, reaching and
intercepting more than one water bearing strata
A. Tube wells
B. Deep wells
C. Shallow wells
D. All of the above
E. None of the Above
13. A rain gauge station DELTA was not functioning during a storm has occurred in a
water shed. The said rainstorm was recorded in the three surrounding stations in
the area. The stations where ALPHA, BETA and CHARLIE with 8.5, 6.7 and 9.0
cm, respectively. If the accumulation area ratio for the stations are 75, 84, 70 and
90 cm, respectively. Estimate the storm rainfall at station D.
A. 6.20 cm
B. 7. 23 cm
C. 11.23 cm
D. 9.65 cm
E. None of the above
14. The meander pattern of a river is developed by
A. Average discharge
 B. Dominant discharge
C. Maximum discharge
D. Critical discharge
E. None of the above
15. The following are the pan evaporation data of the year 2020 in a lake in cm. 16.7,
14.3, 17.8, 25.0, 28.6, 21.4, 16.7, 16.7, 16.7, 21.4, 16.7, 16.7. The water spread
area in a lake nearby in the beginning of January in that year was 2.80 km2 and at
the end of December, it was measured as 2.55 km2. Calculate the loss of water due
to evaporation on that year. Use pan coefficient of 0.7.
A. 4.29 x 106 m3
B. 2.29 x 106 m3
C. 3.39 x 106 m3
D. 2.49 x 106 m3
E. None of the above
16. A watershed has a recurrence interval of 35 cm rain storm of 12 years.
A. The place will definitely have 35 cm rain storm after every 12 years
B. The place may have 35 cm rain storm after every 12 years
C. The place may have 35 cm rain storm within a set of 12 years twice
D. All are correct
E. None of the above
17. Water stored in the reservoir below the minimum pool level is known as
A. Dead storage
B. Useful storage
C. Conservation storage
D. Base storage
E. None of the above
18. A water channel has a known bottom width of 200 m and a measured depth of 6
m and side slopes determined at 1:1. If the depth of the channel is increased to 9
m by dredging, determine the percentage increase in velocity of flow in the
channel.
A. 18 %
B. 19 %
C. 20 %
D. 21 %
E. None of the above
19. The percentage of freshwater present in the total amount of water.
A. 50 %
B. 1 %
C. 25 %
D. 3 %
E. None of the above
20. The total recorded runoff volume within 6 hours storm duration with assumed
uniform intensity of 15mm/hr is 21.6M m3. If the area of the basin is 300 sq. km.,
find the average infiltration rate.
A. 1 mm/hr
B. 2 mm/hr
C. 3 mm/hr
D. 4 mm/hr
E. None of the above
21. In a location under test, the average net radiation is 185W/m2, air temperature is
recorded at 28.5 oC, RH at 55%, wind speed observed at 2.7 m/s at a height of 2
m. Compute the open water evaporation rate using energy method.
A. 7.63 x 10-8 m/s
B. 6.63 x 10-8 m/s
C. 5.63 x 10-8 m/s
D. 4.63 x 10-8 m/s
E. None of the above
22. Run off is mostly affected by this climatic factor
A. Season of the year
B. Rainfall duration and intensity
C. Meteorologic conditions before the storm
D. Soil conditions before the storm
E. None of the above
23. In computing using the Soil Conservation Service method (curve number
method), if the curve number is equal to 100, this indicates that;
A. The run off is zero
B. The rainfall is equal to the run off
C. The rainfall is less than the run off
D. Rainfall is highly erosive
E. None of the above
24. The basin of interest has a shape of pear. The length of travel of several drainage
canals within the system are the following; 6300 m, 4300 m and 7,600 m.
Compute for the time of concentration if the elevation difference of all the canals
is 25 m. The total area of the basin is 2590 ha.
A. 2.3 h
B. 1.5 h
C. 2.9 h
D. 7.8 h
E. None of the above
25. Estimate the total volume of rainfall in a watershed if the total rainfall is 29 mm
on an area of 183 km2.
A. 5.307 x 109 m3
 B. 5.307 x 106 m3
C. 5.307 x 103 m3
D. 5.307 x 1012 m3
E. None of the above
26. During rainstorm, run off is created when this property of soil surface is being
exceeded
A. Percolation rate
B. Erodibility
C. Permeability
D. Infiltration rate
E. None of the above
27. During channel flows, this type of load is intermittently moving as it is being
carried by water along the stream.
A. Suspended load
B. Bed load
C. Temporary load
D. Saltating load
E. None of the above
28. The length of a meander is the distance along the river between the tangent point
of one curve to the tangent point of
A. The reverse curve
B. Next curve of the same order
C. Reverse curve plus width of the river
D. All of the above
E. None of the above
29. Isopiestic lines are contours that are
A. Drawn to represent water table
B. Drawn to represent piezometric heads
C. Drawn to represent piezometric surface
D. All of the above
E. None of the above
30. It refers to the distance from center of the pumped well where no lowering of the
water table is observed.
A. Well radius
B. Radius of interference
C. Radius of influence
D. Drawdown curve
E. None of the above
31. If the irrigation efficiency in farm operation being conducted in a rice farm is
80%, conveyance losses are measured at 20% and the actual depth needed for
watering is 16 cm. Compute for the depth of water required at the canal outlet.
 A. 25 cm
B. 30 cm
C. 35 cm
D. 40 cm
E. None of the above
32. The type of irrigation to be installed is trickle system. It is determined that the
maximum allowable depletion is 35 %. The moisture area is 46 %. The root depth
of crops is 1800 mm. The soil water holding capacity is 95 mm. The water
requirement is at 5 mm. The canopy is 75 %. The electrical conductivity of
saturated paste extract is 8 deciSiemens per meter and the electrical conductivity
of irrigation water is at 0.3 deciSiemens per meter. Compute the maximum net
irrigation depth.
A. 17.211 mm
B. 13.345 mm
C. 15.295 mm
D. 14.318 mm
E. None of the above
33. In an installed sprinkle irrigation system, the distance of irrigation machine
movement is 60 m. The velocity is 36 m/hr. The discharge of gun sprinkler is 50
m3/hr. Compute the value of precipitation in mm.
A. 19.263 mm
B. 23. 148 mm
C. 21. 821 mm
D. 25. 332 mm
E. None of the above
34. In a given square area of 640,000 m2, a center pivot system for irrigation is being
used with an irrigation efficiency of 70%. The maximum daily evapotranspiration
is recorded at 7.6 mm. The effective radius of end sprinkler is measured at 14 m.
The readily available water is 40 mm. The maximum irrigation depth is 18 mm.
Compute for the discharge of the center pivot system.
A. 3.516 m3/s
B. 4.516 m3/s
C. 1.516 m3/s
D. 2.516 m3/s
E. None of the above
35. The irrigation system being used in a fruit trees plot is trickle system. There are 4
emitters assigned in each tree. The root depth is 1.5 m. The distance of emitters is
1m, w=1.2 m, Sp=3 m and Sr=4 m. Determine percentage of wetted area.
A. 40 %
B. 45 %
C. 50 %
 D. 55 %
E. None of the above
36. In a grain farm of 5 ha, the volume of irrigation is 52000 m 3 and the
evapotranspiration is 1000 mm. Compute for the irrigation efficiency.
A. 94 %
B. 95 %
C. 96 %
D. 97 %
E. None of the above
37. Compute for the specific capacity of an open well from the following data. Initial
depression head=5 m. Final depression head=2 m. Time of recuperation=2 hrs.
Diameter of well=3 m.
A. 3.24 m3/hr/unit head
B. 2.24 m3/hr/unit head
C. 1.24 m3/hr/unit head
D. 4.24 m3/hr/unit head
E. None of the above
38. Compute the diameter of an open well to give the discharge of 3 l/s. The
depression head is recorded at 3 m. The specific yield is 1 m3/hr/m2.
A. 4.14 m
B. 2.14 m
C. 1.14 m
D. 3.14 m
E. None of the above
39. Compute for the bulk density of a soil when a soil core of 10 cm diameter and 8
cm length weighs 1113.14 g immediate after sampling and measured 980.57 g
after oven drying at 105 oC.
A. 1.96 g/cm3
B. 1.26 g/cm3
C. 1.86 g/cm3
D. 1.56 g/cm3
E. None of the above
40. Solve for the porosity of a soil when particle density is 2.65 g/cm 3 and bulk
density of that same soil is 1.56 g/cm3.
A. 45 %
B. 41 %
C. 70%
D. 69%
E. None of the above
41. During survey, a soil sample was drawn using a core sampler having an inside
diameter of 10 cm and a length of 5 cm. The weight of the fresh core is 700 g and
 the weight of the oven dried core is 625 g. Solve for the soil water content volume
basis.
A. 9 %
B. 10 %
C. 11 %
D. 12 %
E. None of the above
42. A permeameter of 0.40 m diameter discharges 1.5 liters of water every half hour.
The soil was packed to depth of 0.45 m and a constant head of 0.15 m was
maintained. Solve for the hydraulic conductivity.
A. 5.79 cm/hr
B. 0.79 cm/hr
C. 1.79 cm/hr
D. 6.79 cm/hr
E. None of the above
43. Choose the correct sequence of the part of a canal system from the following
A. Head works-distributary-branch canal-minor
B. Head works-main canal-branch canal-distributary-minor
C. Head works-main canal-branch canal-minor-distributary
D. Head works-branch canal-main canal-distributary-minor
E. None of the above
44. Silting of water channels is a major problem in open channel flows. The main
cause of silting is,
A. None regime section
B. Inadequate slope
C. Defective head regulator
D. All of the above
E. None of the above
45. An outlet is said to be proportional if its flexibility is,
A. Zero
B. Less than one
C. More than one
D. One
E. None of the above
46. The following statement are correct except,
A. In free flooding irrigation, water is admitted at one corner of a field and is
allowed to spread over the entire area
B. In check method of irrigation, the field is divided into smaller components
and water is admitted to each in turn
C. In furrow irrigation, water is admitted between rows of plants in field
D. All of the above
 E. None of the above
47. In construction of canal head works for irrigation, the best location to construct
the structure is,
A. Boulders stage of river
B. Delta stage of river
C. Rock stage of river
D. Trough stage of river
E. None of the above
48. These are canals constructed for draining off water from water logged areas
A. Contour canals
B. Logged canals
C. Inundation canals
D. Drains
E. None of the above
49. The most hydraulically efficient trapezoidal channel section to carry a discharge
of 5 m3/s on a bed material with a roughness n of 0.02 and a bottom slope of 1 in
800 should have a bottom width of,
A. 1.65 m
B. 2.85 m
C. 1.35 m
D. 2.65 m
E. None of the above
50. It is defined as the rate of movement of ground water per unit area which results
from a unit of hydraulic gradient
A. Infiltration capacity
B. Percolation rate
C. Hydraulic conductivity
D. Base flow rate
E. None of the above
51. It is an aquifer where groundwater is overlain by an impervious layer, acted upon
by hydrostatic pressure greater than 101.325 kPa.
A. Aquifuge
B. Aquiclude
C. Aquifer
D. Confined aquifer
E. None of the above
52. A type of rainfall that resulted from convergence of air masses into a low pressure
area
A. Convective
B. Cyclonic
C. Orographic
 D. All of the above
E. None of the above
53. The process of drawing lines on a topographic map to determine boundaries
between adjacent watersheds
A. Watershed
B. Watershed divide
C. Watershed delineation
D. Watershed lining
E. None of the above
54. The rate of decrease of temperature with increase in elevation,
A. Convection rate
B. Updraft rate
C. Deflection rate
D. Lapse rate
E. None of the above
55. Water being held by surface tension in a soil particle that forms like a continuous
film
A. Groundwater
B. Hygroscopic water
C. Capillary water
D. Gravitational water
E. None of the above
56. The data format that would likely represent a file exported from AutoDesk-
AutoCAD.
A. .TXT
B. .LAS
C. .SHP
D. .DXF
E. None of the above
57. It is a GIS dataset that is constantly accessed, manipulated and or revised by
multiple users.
A. Shapefiles
B. KML files
C. Enterprise geodatabase
D. Personal geodatabase
E. None of the above
58. To filter data based on the content stored in a field refers to this kind of
characteristic. This data can help show the information based on the defined
parameters.
A. Cartographic query
B. Spatial query
 C. Locational query
D. Attribute query
E. None of the above
59. Compute for the specific energy of a water channel with y=0.5m, b=1.0,
q=0.7m3/s.
A. 0.6 m
B. 0.7 m
C. 0.8 m
D. 0.9 m
E. None of the above
60. Determine the flow condition of the rectangular concrete lined channel with b=2
m wide, slope=0.001 m/m and a discharge of 1m3/s. Use n=0.015
A. Supercritical
B. Subcritical
C. Critical
D. Cannot be determined
E. None of the above
61. An earth dam requires 1200 m3 of compacted fill. If the desired void ratio of the
fill is 0.6 and the void ratio of the material in the borrow area is 1.1, what is the
volume of material that must be removed from the borrow area?
A. 1,950 m3
B. 750 m3
C. 1,575 m3
D. 825 m3
E. None of the above
62. Estimate the discharge from a 0.3 m diameter well fully penetrating a confined
aquifer with the following data:
Aquifer thickness 26 m
Height of static potentiometric surface
above the top of the aquifer 85 m
Drawdown at 20 m radius 35 m
Drawdown at 100 m radius 05 m
Aquifer medium mixed sand (k=2x10-5 m/s)
A. 58 L/s
B. 61 L/s
C. 64 L/s
D. 55 L/s
E. None of the above
63. Estimate the hydraulic conductivity of an unconfined aquifer from the following
test data:
Depth to restrictive layer 21 m
 Depth to static water table 4m
Drawdown at 10 m radius 8m
Drawdown at 50 m radius 1.2 m
Well discharge 6 L/s
-5
A. 1.8 x 10 m/s
B. 2.8 x 10-5 m/s
C. 1.2 x 10-5 m/s
D. 2.2 x 10-5 m/s
E. None of the above
64. Compute the wetland area required to reduce ammonia concentrations of an
inflow stream (47,450 m3/yr) by 50%. The inflow concentration to the surface
flow wetland was 200 mg/L and the background and the concentration of
ammonia in the wetland was 25 mg/L. Consider the rate constant of 18.
A. 0.13 ha
B. 0.34 ha
C. 0.22 ha
D. 0.53 ha
E. None of the above
65. Which of the following bioengineering technique requires the least energy level?
A. Green terramesh
B. Envirologs
C. Brushmattress
D. Coir mat
E. None of the above
66. A cylindrical double twist wire mesh unit, lined with coconut husk fiber and filled
with a mixture of rock and soil.
A. Coir roll
B. Coir mat
C. EnviroLog
D. Brushmattress
E. None of the above
67. It refers to the potential of the rain to detach soil particles as it impacts the
ground. It is a characteristic of a rainfall within a given period.
A. Erodibility
B. Erosivity
C. Attack velocity
D. Rain erosion coefficient
E. None of the above
68. The watershed that fed water to an irrigation dam is generally vegetated. Which of
the following is not a benefit of vegetation?
A. Reduce peak run off rates
 B. Reduce time of concentration
C. Increases infiltration capacity
D. Reduce sheet erosion of soil
E. All of the above
69. If the soil loss was 16 Mg/ha on a rolling terrain farm, K = 0.1, l = 120 m, s = 8%,
C = 0.2, and P = 0.6 (for contouring). Compute for the terrace vertical interval to
reduce the soil loss to the terrace channel to 7Mg/ha.
A. 3.4 m
B. 1.2 m
C. 2.3 m
D. 1.7 m
E. None of the above
70. Determine the emission uniformity of a system subunit that uses an emitter with
constants (K) = 0.3, emitter discharge exponent (x) = 0.57, manufacturer’s
coefficient of variation (Cv) = 0.06 and two emitters per plant with average
pressure of 100 kPa and minimum pressure of 90 kPa.
A. 56 %
B. 89 %
C. 75 %
D. 92 %
E. None of the above
71. It is a type of soil where neither sand, silt or clay is predominant
A. Loam
B. Humus
C. Compost
D. Garden soil
E. None of the above
72. It is the tiniest of all soil particles and can only be seen under electron microscope
A. Clay
B. Silt
C. Soil colloid
D. Soil suspension
E. None of the above
73. In the Philippine market, the typical ammonium sulphate available is,
A. 45-0-0
B. 14-14-14
C. 21-0-0
D. 0-0-60
E. None of the above
74. Vigna radiata is a;
A. Bush sitao
 B. Rice bean
C. Castor bean
D. Mungbean
E. None of the above
75. It is the well-known pH range of neutral soils
A. 7.4-8.1
B. 5.5-6.2
C. 4.4-5.1
D. 6.6-7.3
E. None of the above
76. The salinity of brackish water is;
A. < 2 g/L
B. 2-34 g/L
C. >34 g/L
D. All of the above can be correct
E. None of the above
77. A management intensity in aquaculture where there is no control of water quality
A. Extensive management
B. Semi-intensive management
C. Intensive management
D. Semi-extensive management
E. None of the above
78. Fish feeds which has the highest quality protein source commonly available
A. Soybean meal
B. Crustacean meals
C. Fats and oils
D. Fish meal
E. None of the above
79. Refers to an enclosure which is either stationary or floating, made up of nets or
screen sawn or fastened together and installed in the water with opening at the
surface
A. Fish pen
B. Fish pond
C. Fish cage
D. Fish sanctuary
E. None of the above
80. Normal acclimation of biofilters in aquaculture would take about
A. 1 week
B. 2 weeks
C. 3 weeks
D. 4 weeks
 E. None of the above
81. It is the current characteristic which is under the 21st century management
A. Rigidity
B. Reactivity
C. Size and scale
D. Information sharing
E. None of the above
82. Man Juan bought a product at an online selling outlet. Upon receiving the
product, he feels happy because it satisfies the need. It can be said that the product
has
A. Value
B. Price
C. Utility
D. Importance
E. None of the above
83. The 4 P’s of marketing
A. Product, price, place, process
B. Process, product, people, purity
C. Product, price, place, promotion
D. Product, place, publicity, price
E. None of the above
84. Indicates the time and arrangement of crops within a particular area
A. Cropping sequence
B. Cropping combination
C. Cropping schedule
D. Cropping pattern
E. None of the above
85. A sight taken on an unknown elevation,
A. Backsight
B. Foresight
C. Intermediate sight
D. Elevation sight
E. None of the above
86. It is the condition when someone is failing to reject the null hypothesis even when
it is false is,
A. Alpha
B. Beta
C. Type I error
D. Type II error
E. None of the above
87. Refers to focus groups, individual respondents and panels of respondents
 A. Pointed data sources
B. Itemized data sources
C. Secondary data sources
D. Primary data sources
E. None of the above
88. The scale which categorizes the events in collectively exhaustive manner and
mutually exclusive manner can be classified as.
A. Valid scale
B. Nominal scale
C. Discrete scale
D. Continuous scale
E. None of the above
89. Which technique is used in finding solutions for optimizing a given objective,
such as profit maximization or cost reduction under certain constraints?
A. Quailing theory
B. Waiting line
C. Queuing theory
D. Linear programming
E. None of the above
90. In optimization graphical representation, the bounded region is known as
A. Solution
B. Basic solution
C. Optimal solution
D. Feasible solution
E. None of the above
91. An operations research technique which helps minimizing total waiting time and
service costs is
A. Quailing theory
B. Waiting line
C. Queuing theory
D. Linear programming
E. None of the above
92. Which of the following is a type of error in surveying?
A. Personal error
B. Natural error
C. Instrumental error
D. Systematic error
E. None of the above
93. A line was determined to be 2395.25 m when measured with a 30-m steel tape
supported throughout its length under a pull of 4 kg and at a mean temperature of
35 oC. Determine the correct length of the line if the tape used is of standard
 length at 20 oC under a pull of 5 kg. The cross-sectional area of the tape is 0.03
cm2 and its coefficient of linear expansion is 0.0000116/oC, and the modulus of
elasticity of steel is 2.10 x 106 kg/cm2.
A. 2395.71 m
B. 2394.79 m
C. 2395.63 m
D. 2394.87 m
E. None of the above
94. A piece of rope is cut into two segments and each segment is formed into a circle.
The sum of the areas of the two circles is 408.41 cm2. Find the difference between
the radii of the two circles if the rope is 100.53 cm long.
A. 1.8 cm
B. 2.0 cm
C. 2.2 cm
D. 2.3 cm
E. None of the above
95. Compute for the integral 3dx/5x using lower limit of 2 and upper limit of 4.
A. 1.438
B. 0.42
C. 1.85
D. 0.35
E. None of the above
96. The scientific name of a rabbit
A. Oryctolagus cuniculus
B. Cavia porcellus
C. Columbidae
D. Gallus gallus domesticus
E. None of the above
97. It is an abnormal or difficulty of labor during parturition of some animals
A. Dysplasia
B. Metaplasia
C. Anaplasia
D. Dystocia
E. None of the above
98. It refers to a breeding male duck
A. Squab
B. Drake
C. Gander
D. Gabbler
E. None of the above
99. It refers to a male carabao that is castrated or unsexed while young
 A. Cara-cow
B. Cara-heifer
C. Cara-steer
D. Cara-calf
E. None of the above
100. It is the period of heat and greatest receptivity to male. The rapture of
ovarian follicles happens in this stage in most of farm animals.
A. Proestrus
B. Estrus
C. Metestrus
D. Diestrus
E. None of the above