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Biology Waec 2015 Expo Runz

+Tuesday, 21st April, 2015:
Biology 2(Essay) --- 2.00pm - 3.40pm
Biology 1(Obj) --- 3.40pm. - 4.30pm

(1a)In sexual reproduction of Rhizopus,resistant spherical spores are formed,called zygospores,which are thick-walled,and it makes them resistant to environmental hardships.The zygospores are the only diploid phase of Rhizopus stolonifer reproduction.They are composed of two suspensor cells which are former gametangia or hyphae.There is a suspensor on either side of a large,rough,dark brown spore.They suspensor cells are present to provide support.The zygospores forms from two special haploid haphae of opposite mating types that touch due to hormonal proximity to each other.The two cytoplasms intermingle,also known as plasmogamy.As this occurs,the nuclei of both parents enter the conjuction,causing the resting spore to develop.
zygospore has fully formed,meiosis occurs and haploid spores are formed and dispersed.The zygospore can become dormant for several months at a time.Meiosis still occurs and sporangium similar to the asexually produced sporangium is created when the zygospore finally cracks open.

(1b)i.Adrenaline.(1bii).Adrenal gland
(1biii)i.It increases heart beat and respiration.ii.it increases sugar content of blood.iii.It aids dilation of the pupils.iv.It increases the muscular tone.v.It is responsible for shivering during cold.vi.It is associated with fear and anxiety.

(1ci)(draw a table before writing)
i.Animals have specialized excretory organs while plants have no specialized organ.ii.in animals,water is excreted through the skin while in plants,water is excreted through the lenticels.iii.

(1cii)Stomata and lenticels
the leaf of a flowering plant is adapted for photosynthesis because carbon(iv) oxide, water, chlorophyll, sunlight, mineral, suitable temperature and enzymes are present.
carbon(iv) oxide is diffused into the intercellular spaces through stomata of the leaves and later diffuses into the mesophyll cells containing chloroplasts. menral salts derived from the soil pass into the roots of the plant by osmoisis and dissolved mineral salts are conducted by xylem from roofs of stem. the light from sunlight is trapped.

the tapeworm is an endoparasite
carries out parasitic feeding on its
food is absorbed though its entire body
surface. the hooks and suckers are
used for
attachment to the intestine of the host
avoid dislogment. the entire body surface is
used also for the absorption of food.
iodine (2ciii)
three benefits are:
-it eliminates constipation
-it helps to stimulate movement of bowel
-it helps to balance intestinal content
-for growth
-aids reproduction
-production of enzymes

(3ai)Sewage can be defined as the domestic households, industrial and agricultural practices produce wastewater that can cause pollution of many lakes and rivers
-Increased organic matter (from the sewage) breaking down in the river reduces the amount of dissolved oxygen in the water body as the decomposition process uses up the available dissolved oxygen. Fish and other aquatic life need that dissolved oxygen in the water to live.
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and be rest assured you have passed biology. (cool)

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Posted By KellyChi On 10:39 Mon, 20 Apr 2015

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