Waec 2018 Biology Obj And Theory Answers – May/June Expo

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Biology OBJ: 

1BDDCCBCDBC
11ADCDCCAACC
21CAABBBBCBC
31CABCCACDAA
41ABBDDADDAB

Theory:

(4ai)
Gene is the discrete unit of inheritance which are found in the chromosomes of all cell.

(4aii)
A hybrid is an offspring obtained from the cross-breeding of the species that are not closely related.

(4aiii)

Trait is the characteristic factor of an individual which are hereditary.

(4b)

Draw the diagram
Phenotyoic ratio= 3:1
Genotypic ratio= 1:2:1

(4c)
The four transmittable characters in plants are:
-Height
-Colour
-Shape of fruit
-Size of Leaf

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6ai)
Chemosynthesis is the biological conversion of one or more carbon-containing molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic compounds (e.g., hydrogen gas, hydrogen sulfide) or methane as a source of energy, rather than sunlight

6aii)
i)Bacteria
ii)methanogenic archaea

6b)
Nitrogen — 78 percent.
Oxygen — 21 percent.
Argon — 0.93 percent.
Carbon dioxide — 0.04 percent.

6c)
i)They are composed of relatively few species of plants
ii)The salt level of the habitat is high
iii)High flooding rate
iv)extreme temperature and salinity fluctuations.

6cii)
Roots of salt marsh plants help stabilize the sandy substrate and trap and hold nutrients and detritus that flow through with each tidal cycle. This detritus trap helps feed bacteria, algae, and invertebrates. These root tangles also provide critical refuge for small fish and other animals.

6d)
i)Pulmonary Tuberculosis
ii)Cholera
iii)Pertussis
iv)Salmonellosis:

6dii)
i)food poisoning
ii)food spoilage
iii)Low market value of food

6e)
the person need plenty of rest and diet rich in protein, fruits an vegetables and take plenty water

6f)
Tabulate
Tillage
i)the soil is prepared mammally or mechanically
ii)conserves soil nutrients
iii)good for farm practise
Bush Burning

i)fire is used to remove plants
ii)destroyes soil nutrients
iii)a bad farm practise

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3ai)
renewable resource is a resourcewhich can be used repeatedly and replaced naturally.

3aii)
nonrenewable resource is a resource of economic value that cannot be readily replaced by natural means on a level equal to its consumption.

3bi)

i)oxygen
ii)fresh water

3bii)
I)oil
ii)natural gas

3c)
i)Regulated and Planned Cutting of Trees.
ii)Control over Forest Fire.
iii)Reforestation and Afforestation.
v)Check over Forest Clearance for Agricultural and Habitation Purposes.
iv)Proper Utilization of Forest and Forests Products.

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2a)
i)carbon dioxide
ii)Nitrogen

2b)
i)CO2 is used by plants to photosynthesize carbohydrates.
ii)Nitrogen is a major component of chhlorophyll

2ci)
Variegated leaf is a leaf that has green parts (where the cells contain chlorophyll) and non green parts (where there is no chlorophyll).

2cii)
The green parts

2ciii)
i)The parts without chlorophyll do not photosynthesise
ii)the cells contain chlorophyll

2civ)

Magnesium

2d)
Fill The Table
Tabulate
i) Halozoic- Human,venus fly trap
ii)parasitic- tape worm,Venus fly trap
iii)symbiotic- lichen
iv)sapraphytic- Rhizopus,mushroom,housefly

v)autotrophic- spirogyra,water leaf plant,elephant grass

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