Biology-Obj

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Biology Theory Ans
1 ai)
A sperm cell consists of a head, middle piece and a whip- like tail . At the anterior end of the head is a structure called Acrosome. This Acrosome contains a liquid which facilitates the entry of the sperm into an egg . The middle piece contains numerous mitochondria which are involved in producing energy needed for propelling the sperm after ejaculation. The tail is for movement .

1 aii )
A palisade cell contain chloroplasts which makes them a site of photosynthesis in the leaves of those that plants that contain them , converting the light to the chemical energy . Beneath the palisade mesophyll are the spongy mesophyll cells , which also perform photosynthesis . They allow the passage of gases through the intercellular spaces in them .

1 b )
Draw the Diagram

1 c )
In a tabular form :
Under mammals:
i ) Mammals give birth to their young ones alive
ii) Mammals product amniotic eggs .
Under amphibians:
i ) Amphibians lay eggs
ii) Amphibians do not produce amniotic eggs .

1 d )
i ) Use of condoms/ pills .
ii) Withdrawal method
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4 ai)
Gene is the discrete unit of inheritance which are found in the chromosomes of all cell .

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

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

4 b )
Draw the diagram
Phenotyoic ratio = 3 : 1
Genotypic ratio = 1 : 2 : 1

4 c )
The four transmittable characters in plants are :
– Height
– Colour
– Shape of fruit
– Size of Leaf
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6 ai)
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

6 aii )
i ) Bacteria
ii) methanogenic archaea

6 b )
Nitrogen — 78 percent .
Oxygen — 21 percent .
Argon — 0 . 93 percent .
Carbon dioxide — 0 . 04 percent .

6 c )
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.

6 cii )
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 .

6 d )
i ) Pulmonary Tuberculosis
ii) Cholera
iii ) Pertussis
iv ) Salmonellosis:
6 dii )
i ) food poisoning
ii) food spoilage
iii ) Low market value of food

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

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

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

3 bi)
i ) oxygen
ii) fresh water
3 bii )
I ) oil
ii) natural gas

3 c )
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 .

3 d )
i ) increases soil nutrients
ii) increases soil air
iii ) improve soil structure
iv ) pollution of the soil

3 e )
i ) AA
ii) AO
iii ) BB
iv ) BO
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2 a )
i ) carbon dioxide
ii) Nitrogen

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

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

2 cii )
The green parts

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

2 civ )
Magnesium

2 d )
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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Completed
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