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The phenotypic ratio will be two homozygous tall and two heterozygous tall... That implies that all four offsprings will come out tall.

No expanded working has been attached for this question yet. The verified answer is Option B.

No expanded working has been attached for this question yet. The verified answer is Option B.

(ii) (v) Fruit type: Berry (iii) Examples: Guava, pepper, garden egg. pawpaw, oranges, citrus fruit. (iv) True fruit. (v) It is developed from fertilized ovary. (vi) Classes of food in Specimen H/ Tomato fruit: - Vitamins. Minerals -Salts - Cabohydrates - Water (O0) common feature: They are all leaves/ they all have leaves. (ii) J/Gloriosa: - Tip of midrib/leaf into a tendril. - Leaves are sessile/no petiole/leaf stalk, - Leaf with parallel veins. J/Pumpkin: Tendril at tne axile of the leaf. -Hairy leaf - Net/recticulate venation. Specimen K/Brvophvllum: Leaf bear buds at notches of margin. - Leaf is succulent/fleshy/swollen. - Leaf has waxy surface. Specimen L/Onion Bulb: - Presence of swollen leaf bases (witn reserve food). - Stem reduced to disc like structure, -Terminal and axilary buds present. - Presence of leaf scales -Adventitious roots present. (iii) Mode of vegetative propagation of K and L: K/Bryophylum: Sprouting of adventitous buds; at margins of leaves. Specimen L/Onion bulb: Terminal/lateral buds, sprout of new aerial shoots. (c) Biological significance of K: Vegetative reproduction. -Storage organ (store water, mineral salts, etc). characteristics of parent plant are preserved. - Can photosynthesize.

The phenotypic ratio will be two homozygous tall and two heterozygous tall... That implies that all four offsprings will come out tall.

(a)(i) Arteries: carry blood away from the heart. transport oxygenated blood with the exception of pulmonary artery. (ii) Capillaries: - permit exchange of materials between blood and tissues. . links the arteries and veins. (iii) Veins: - carry blood to the heart. transport deoxygenated blood except pulmonary vein. (iv) Xylem: - transports water/dissolved mineral salts serves as a supporting tissue/strengthening tissue. (v) Phloem: - transports manufactured food/auxins/plants hormones performs strengthening supporting function. (b) Changes in blood composition: (i) Lungs: - oxygen is added to the blood. carbon dioxide is removed from the blood. water is removed from the blood. (ii) Liver: - urea is added to the blood. hormonal level is reduced. glucose level reduced. worn out erythrocytes are removed from the blood. (iii) Kidneys: Water, urea, some glucose; mineral salts are reduced in the blood. (iv) Small Intestine: - simple sugars/glucose, amino acids; water; salts and vitamins are added to the blood. (c) Cellular Components of blood: Red blood cells/erythrocytes; white blood cells/leacocytes; and platelets/ thrombocytes.

(a) Transpiration: - This is the loss of water; in vapour form; from the aerial parts/stomata/lentice/stem/leaf of a petal. (b) (i) Types of transpiration: - stomatal transpiration. - lenticular transpiration - cuticular transpiration (ii) Factors affecting rates of transpiration: - light intensity/light - temperature - wind - availability of soil water/water -humidity - leaf surface area - leaf structure/thick cuticle - sunken stomata/hairy/spiny - root system (deep/shallow roots) (c) Mechanism of stomata! opening: - when the solute concentration of the guards cells is high. water flows from neighboring epidermic/cells into the guard cells. by osmosis the volume and turgidity of the guard cells increase the thin outer walls of the guard cells stretch more than thicker inner walls. causing the guard cells/stomata to open when the solute concentration is low. water flows out of the guard cells by osmosis. the volume and turgidity decrease causing the guard cell to become flaccid; and the stomatal pore is closed. (d) (i) Similarities between transpiration and sweating: - Both involve loss of water from the body of the organism. both processes result in cooling. water is lost through pores. (ii) Differences: Transportation sweating Occurs in plants through stomata/lenticles occurs in mammals/skin/through sweat pores Transpiration involves only loss of water loss of water, salts and nitrogenous waste water is lost in the form of vapour water is lost in liquid form occurs during the day occurs both day and night

(a)(i) Population: This is a group of individuals; of the same species; inhabiting a particular area/habitat; at a particular point in time. (ii) Competition: - This is the interaction between members of the same population/ species/intra - specific/two or more populations/species/inter - specific; occupying the same trophic level; to obtain mutually needed resources; that are short in supply in their environment. (iii) Succession: - This is the step by step/orderly; and gradual replacement of communities; arising from a change in the environment/environmental factors; which leads to a climax/stable community. (b) (i) Sources of noise pollution: - Electronic sound system Sirens Generators Airplanes Factory machines Industrial machines Canons shots/guns firing Artillery firing Quarry activity/construction site Motor vehicles. (ii) Prevention: Legislation Education/public enlightenment Siting factories, industries, military site away from residential areas Use of sound proof/silent generators. (c)(i) Effects of smoke on humans: - Causes breathing difficulties. Causes injury to the lining of respiratory tracts/ lungs. Reduces visibility; reduces photosynthesis leading to lower crop yield. Causes discomfort to the eyes. Contains carbon monoxide which is injurious to man. (ii) Effects of sewage on human: Untreated sewage discharged into water bodies makes water unfit for drinking/swimming may cause spread of water borne diseases/correctly named borne disease. its toxic to aquatic organisms thereby depleting food source for man. makes water unsafe for domestic use. leads to offensive odour. poisonous substances may enter the food chain which is unsafe for man.

(a) Main stages of mitotic division: Prophase - Chromosomes appear as two threads/chromatids chromatids are long thin and/later become shorter and thicker; and joined together at the centromere; the nuclear memberane; and the nucleolus disappear spindle fibres form in the cytoplasm; with a pair of centrioles; one at each pole. Metaphase: spindle formation is completed the chromosomes are arranged at the equator of the spindle attached by their centromeres; centromeres divide; and begin to move apart. Anaphase The paired chromatids are pulled apart/separated migrate/move towards opposite poles spindle fibres shorten; chromatids reach the poles. Telophase - Fibres disappear, nuclear materials and nucleolus are formed bounded by nuclear membrane the cell constricts to form two daughter cells. (b) Importance of mitosis: Promotes cell growth replacement/repair of damaged tissues basis of asexual/ vegetative reproduction produces genetically identical offspring which are identical to the parents maintains the diploid number of the chromosome of the cell.

(a) Hormones - These are chemical substances secreted by endocrine/ductless glands, directly into the blood/ circulatory system, which on reaching a target organ, stimulate activity of that organ. Hormonal Nervous Transmission is chemical transmission is mechanical and chemical slow transmission Rapid transmission Response is wide spread Response localized Target organs receive response effector organs receive response Long last response short-lived response pathway not specific through blood pathway specific through nerves fibres (c)(i) Effects of over-secretion: - Over active/Hyperactive/Irritable/nervous. Excessive growth/gigantism Loss of weight Enlarged thyroid gland/exothalmic goitre Accelerated/increased heartbeat Protrusion/bulging out of eyeball. (ii) Effects of under-secretion: - Cretinism/dwarfism in children. Overweight/increase in subcutaneous fat/obesity. Physical/mental sluggishness in adults. Reduced heart rate. Lowered/reduced metabolic rate/ myxceodema. Goitre formation/hyperplastic goiter. (d) Labels: Receptor organ, sensory neurone, intermediate/relay neurone; motor neurone, synapse, spinal cord, ventral root, dorsal root, effector organ, spinal nerve.

(a) Modes of nutrition in plants: Autotrophic: Plants manufacture their food; using water from the soil; and carbon dioxide from the atmosphere in the presence of sunlight. Chemosynthetic: These plants manufacture their food; using atmospheric carbon dioxide; and energy from the breakdown of inorganic compounds. Carnivorous: These plants in addition to photosynthesizing have special devices; for trapping and digesting insects and other small organism; to balance a deficiency in nitrogen. (b)(i) Autotrophic: Flowering plant (ii) Chemosynthetic: Nitorsomonas, Nitrobacter, fungi, Nitrococcus. (iii) carnivorous: Pitcher plants, bladderwort; sundew, venus flytrap, butterwort. (c)(i) Addition of nitrogen to soil. Decomposition of dead organic matter: Dead organic matter, are decomposed by putrifying bacteria; into ammonium compounds ammonium compounds are converted to nitrites by nitrifying bacteria, in the soil nitrites are converted into nitrates by nitrifying bacteria in the soil. Nitrogen fixation in root nodules: Nitrogen fixing bacteria; living in the root nodules of leguminous plants Convert gaseous nitrogen in the soil/atmosphere/air-spaces; into nitrates. During thunder storms; the energy from electrical discharge/action of lightning enables atmospheric nitrogen to react with oxygen to form oxides of nitrogen/nitric oxides; which dissolves in rain water to form weak nitric acid; which is washed in the soil and converted into nitrites and nitrates. (ii) Loss of nitrogen from the soil: - Absorption by plant roots. Action of denitrifying bacteria. By action of leaching.

(ii) Type of ovary: Superior Ovary. (iii) Ovary is located at a higher position than receptacle/on top of receptacle/above point of attachment of other fioral parts. (iv) Description of petals and sepal: Sepals are of the same colour as petals/petaloid. Sepals are smaller than petals in size. Petals are fan shaped; brightly coloured. Standard petals is tubular/flat with marks. - One sepal is keel shaped. (v) Function of special petal: It guides insect/bee to the nectar. (vi)- Brightly coloured petal attracts insects which pollinate flower - Large petals which are easily seen. - Presence of nectar, attract insect which enhance cross pollination leading to variety and survival of the species. - Sticky stigma to hold pollen grains for pollination. - Sticky/rough pollen grains to ensure pollination/attachment to insects. (b)(i) Type of fruit (Specimen B) Legume/Pod (ii) Examples of legumes: Bean, peas, caesalpinia, crotalaria, Delonix sp., MuCuna. (iii) Mode of dispersal: Explosive mechanism (iv) Biological importance of legumes: - Source of food/protein. - Fixes nitrogen in the roots/soil. - Serves as Cover crop/prevents erosion. - Source of feed for live stock.

(a)(i) Class of specimen C/Cock: (ii) Reasons for class: - Body covered with feathers. - Forelimbs modified into wings. - Mouth modified into beak. (iii) Food items: Grains/any named grain; insects; worms; vegetables. (b)(i) Features for feeding: short, strong/horny beak for pecking food. sharp/strong claws on toes/digit; - for Scratching the suriace of ground in search for food. (ii) Features of locomotion: - Streamlined shape to reduce air resistance. - Forelimbs modified into wings for flying. - Hind limb for walking and running. -Tail feathers for steering and balancing. (c)(i) Observable characters that can be inherited: Colour of feather, shape of comb, shape of beak, eye colour, size of comb, body size; colour of wattle.

Arrange in ascending order 2, 5, 5, 5, 6, 6, 6, 6, 8, 8 Position of median = N/2 = 10/2 = 5th and 6th ∴Median = (6+6) / 2 = 12/2 = 6 Mode the item that repeats itself most = 6 ∴Product of modal and median number = 6 x 6 = 36

Number of grapes = 6 Number of banana = 11 Number of oranges = 13 Total = 30 P(Grape) = 6/30, P(Banana) = 11/30 P(Orange) = 13/30 ∴P(Either grape or banana) = 6/30 + 11/30 = 17/30