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100% WAEC ANSWERS ON Theory BIOLOGY APRIL 19th 2018
i)CO2 is used by plants to photosynthesize carbohydrates.
ii)Nitrogen is a major component of chhlorophyll
Variegated leaf is a leaf that has green parts (where the cells contain chlorophyll) and non green parts (where there is no chlorophyll).
The green parts
i)The parts without chlorophyll do not photosynthesise
ii)the cells contain chlorophyll
renewable resource is a resourcewhich can be used repeatedly and replaced naturally.
nonrenewable resource is a resource of economic value that cannot be readily replaced by natural means on a level equal to its consumption.
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 Utilisation of Forest and Forests Products.
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
Nitrogen — 78 percent.
Oxygen — 21 percent.
Argon — 0.93 percent.
Carbon dioxide — 0.04 percent.
Gene is the discrete unit of inheritance which are found in the chromosomes of all cell.
A hybrid is an offspring obtained from the cross-breeding of the species that are not closely related.
Trait is the characteristic factor of an individual which are hereditary.
Draw the diagram
Phenotyoic ratio= 3:1
Genotypic ratio= 1:2:1
The four transmittable characters in plants are:
-Shape of fruit
-Size of Leaf
Tapeworm; Venus flytrap
Rhizopus; mushroom; housefly.
Spirogyra; waterleaf plant; elephant grass.
6b)nitrogen-78%. ii)oxygen-21%. iii)Co2-0.03%
3di)it improves soil texture & structure.
ii)it improves soil aeration.
iii)it improves decomposition.
iv)it improves soil fertility.
3ei)AA (ii)AS. (iii)SS
6ci)it has high relative humidity (b)it has organic matters.
(c)it has flooded ground.
(d)it has wet,soft,waterlogged & poorly aerated soil.
6cii)the plants have breathing root,they lack strong suppporting tissues.And the leaves may have buoyancy.Eg is algae,lettuce,etc.
6di)Food poisoning. b)gastroeteritis. c)trachoma. d)pneumonia.
6dii)it causes disease. b)it causes indigestion.
c)it leads to waste of income.
6e)the victim will be taken to the health care centre for first aid,blood transfusion,& good nutrition for blood clotting & healings.
6f)a)tillage is the breaking of lump of soil while bush burning is not.
b)bush burning is a farm operation before tillage operation.
c)tillage increase soil fertility,aeration,& decomposition while bush burning does not.