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

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

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

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

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

Given: \(\frac{^6C_r}{^6P_r} = \frac{1}{6}\) Recall the formulas: \(^nC_r = \frac{n!}{r!(n-r)!}, \quad ^nP_r = \frac{n!}{r!}\) Substitute \( n = 6 \): \(\frac{^6C_r}{^6P_r} = \frac{\dfrac{6!}{r!(6-r)!}}{\dfrac{6!}{r!}} = \frac{6!}{r!(6-r)!} \times \frac{r!}{6!} = \frac{1}{(6-r)!}\) So the equation simplifies to: \(\frac{1}{(6-r)!} = \frac{1}{6}\) Therefore: (6-r)! = 6 We know that 3! = 6, so: 6 - r = 3 \(\implies\) r = 3

Let the four numbers be \(a, b, c, d\). - Mean of the four numbers = 5 → a + b + c + d = 20 - Mean deviation of the four numbers = 3 Mean deviation = \(\frac{|a-5| + |b-5| + |c-5| + |d-5|}{4} = 3\) → Sum of absolute deviations = 12 - Mean deviation of the first three numbers a, b, c = 2 → \(\frac{|a-5| + |b-5| + |c-5|}{3} = 2\) → Sum of absolute deviations for first three = 6 - Therefore, absolute deviation for the fourth number: |d - 5| = 12 - 6 = 6 The fourth number = 6 + 5 = 11.

The numbers from 0 to 20 inclusive are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20. Total numbers = 21 Odd prime numbers in this range: Primes must be greater than 1 and have no divisors other than 1 and themselves. Odd primes (exclude 2, which is even): 3, 5, 7, 11, 13, 17, 19 → There are 7 odd prime numbers. 3. Probability = \(\frac{\text{Number of favourable outcomes}}{\text{Total outcomes}}\) = \(\dfrac{7}{21} = \dfrac{1}{3}\)

Test/ Method Observation Inference (i) To a small portion of specimen A, add few drops of reagent F and heat gently. A brick-red/ orange precipitate is observed. Indicates presence of reducing sugar e.g glucose, fructose and galactose (ii) To a small portion of specimen A add few drops of reagent D. blue- black /black color is observed. Indicates presence of starch (iii) To a small portion of specimen A, add small quantity or reagent H, No color change/No change. heat gently for a few minutes and allow to cool. No red precipitate/ No precipitate. No color change/ No change No food content detected iv) To specimen A treated with reagent H heated, add small quantity of reagent E, heat for a few minutes and allow to cool A blue precipitate The blue ppt when heated turn brick red /red Or Brick-red orange precipitate obtained. This indicates presence of starch/ complex carbohydrate or has been hydrolyzed to simple reducing Sugar Or indicates presence of simple reducing sugar. (V) To a small portion of specimen B, add small portion of reagent G Violet/purple color is obtained Indicates presence of protein (vi)Litmus dipped in specimen C No color change/ No change. Color remain the same. it is neutral to litmus paper. Neutral solution/Distilled water/Liquid solvent water present/ no change (b) (i) Examples of food contents in specimens A and B: (1) Specimen A: Reducing sugar/glucose/fructose/galactose e.g. Fruits/oranges/grapes/mango/tomato; Maltose or lactose, e.g. banana /pineapple/lime/coconut milk; Starch, e.g. rice /grains/cereal/ yam/potato/any correctly named food containing starch. Specimen B-Protein e. g meat fish/egg/ milk/ chicken/Cray fish/ beans/ legumes. (i) Importance of specimen A, B and C to man: (1) Reducing sugar provides energy, maintains body temperature, produces heat for oxidation and produces warmth. (2) Starch provides energy, heat or warmth which can be converted and stored as fat and for industrial uses, e.g alcohol productions and laundry. (3)Protein is for growth body building, for repairs or replacement of worn out or damaged cells/tissues/blood cells, synthesis or enzymes or hormones and for red blood making. (4) Water is used as solvent, medium for reactions of particles, Sustenance or lie, cooking/washing/drinking/domestic use, maintenance of body temperature, medium for digestion (C)(i) The Primary source of food contents identified in specimen A and B is Plant/green plant/producers. (ii) Natural Source of specimen C is spring/stream/river/sea/rain/lake/ocean/pond. 2. (a) Specimen I - is a bony fish/Tilapia; Specimen J is a toad/frog/bufo. (ii) Habitat of specimen I is Aquatic; Habitat of specimen J is Terrestrial/land, Fresh water or partial aquatic fresh water. (b) Structural adaptations for movement by specimen J: Short fore-limb (in the four digits for landing); Long and muscular nind - limbs (for hopping/Jumping); Webbed digits/toes of the hind - limbs (for swimming); Streamlined body (for movement in water). (d) Respiratory organs of specimens I and J: Specimen I = gill/gill only; Specimen J bucal cavity/mouth, Skin, Lungs, Nostril. (C)(i) Common features of the respiratory organs of specimen l and J: Thin surface/layer. Large/broad suce area, Moist/moistened/wet surface, -Surface vascularized/ richly supplied with blood vessels, numerous tnin blood vessels. Specimen Floral Number of Parts Color Free/Fuse united Essential or Non-essential K (Hibiscus flower ) Sepals/calyx 5 Green united/fused Non-essential Petals/corolla 5 Red/Pink Free Non-essential Stamens numerous/ / uncountable Above 10 many /plenty Red/Pink/white/ yellow united/fused Essential Stigma 5 Red/Pink free Essential

(a) The principles involved in the following methods of food preservation are: (i) Salting:- It raises the osmotic concentration of food. and removes water from or dehydrates the food (ex - osmosis) to an intolerable level. (ii) Refrigeration: It provides lower temperature within the food, retards (slows down) biological processes in spoilage organisms in food and kills some micro-organisms or slows down the activities of spoilage organisms in food. (iii)Drying: It removes water or moisture and dehydrates food, prevents normal microbial activities which requires water and increases osmotic concentration of food which kills spoilage organism. (iv)Smoking: It creates or generates high temperature/heat Its carbon kills micro-organisms in food, causes dehydration, increases osmotic pressure and hence, killing of the microbes. (v) Chemicals: It chokes /suffocates/ spoilage organisms in food, dehydrates/toxicates spoilage organism in food and finally kills organisms. (b) Problems that may be caused by human over - population are: (1) Reduction of availability of land for agriculture. (2) Shortage of food resulting in competition and starvation. (3) Causes unemployment. (4) Reduces per capita income/causes poverty. (5) Causes outbreak of disease / epidemics/ health hazard. (6) Causes inadequate medical care, social welfare services and shelter. (7) Leads to increased social vices like crimes, juvenile delinquency, drug abuse e.t.c and aggression. (8) Causes inadequate educational facilities and other public utility services. (c) Ways by Which government may increase food production are: (i) Distribution of high quality seeds and other planting stock which are high - yielding, disease/pest/drought resistant. (ii) Distribution of fertilizers and other agro - chemicals at subsidized rate to increase crop yield. (iii) Distribution of tractors/other farm machines/implements for hiring for easy and quicker cultivation of large farm/area of land. (iv) Providing extension services to local farmers to intimate them with modern farming practices/techniques. (v) Establishment of river basin authorities which makes water available for irrigation and dry season farming. (vi) Good roads and stable markets, for easy distribution of products. (vii) Government should make available storage facility to prevent spoilage. (viii) Establishment of research institutes to research on food varieties. (ix) Government should grant agricultural loan to encourage farmers to produce more food.

(a)(i) Hydrosphere is the aquatic portion of the biosphere or life supporting living world or earth. (ii) Examples of hydrosphere are: Lake, Pools, Spring, Oceans, Ponds, Oasis, Rivers, Streams, Manny. (b)(i) The first law of thermodynamics states that energy can neither be created nor destroyed. The second law of thermodynamics states that in any conversion of energy from one state to another, there is always a decrease in the amount of useful energy. (ii) Using the second law of thermodynamics, the energy flow across trophic levels can be explained as follows: The transfer of energy between trophic levels is not 100%. That means it is not completely transferred. Successive levels have less of useful energy and support fewer organisms. Primary producers/plants have the highest amount of energy and when herbivores feed on plants, the energy level is reduced. When carnivores consume the herbivores the energy level is further reduced. (c) (i) Local biotic communities and the state each is found in Nigeria are: Local biotic community State Tropical rainforest . Southern Guinea Savanna Northern Guinea Savanna Sahel Savanna Mangrove/Swamp/Estuarine Edo/Delta/Ondo/Imo/Abia/Lagos/Anam bra/Rivers/Bayelsa/Akwa-Ibom Enugu/Kogi/Benue/Kwara/Oyo/Ebonyi/Osun/Ekiti. Plateau/Kaduna/Bauchi/Niger/Taraba/Adarnawa/Kano. Borno/Kastina/Sokoto/Yobe/Kebbi/Zamfara/Kano/Jigawa. Delta/Cross River/Rivers/Akwalbom/Bayelsa/Ogun/Lagos/Ondo. (ii) Factors affecting marine organisms are: Temperature, Salinity, Pressure, Turbidity/light penetration, Dissolved oxygen, Density of sea water, PH/hydrogen ion concentration, Waves /up-welling of water, Current and Tides. (iii) Adaptive features of sea weeds are; (1) Possession of chloroplast/photosynthesis (2) Absence of lignified tissue which makes them flexible and able to withstand wave actions (3) Possession of hold fast for firm attachment to substratum or rocky surface (4) Body covered with mucilage to reduce desiccation during low tide or on exposure (5) Possession of air bladders for buoyancy.

(a) (i) The law of independent assortment states that each member of alleles or contracting character may combine randomly with either member of another pair. (ii) Findings of Mendel's experiment involving white and red flowered pea plants:- On crossing white and red flowered pea plants, he obtained all red - flowered offspring, but on self-.crossing each of these red- flowered plants he obtained mixtures of red flowered and white flowered plants in the ratio of 3:1 (¾ red / ¼ white flowered). (iii) Illustrations: Key for parental genotype e.g R for red, r for white (b) Blood grouping in man is determined by three alternative genes (alleles) A, B, and 0. A person can only possess two (alleles) of the genes on a pair of homologous chromosomes. 0 is recessive to both A and B, hence it is possible to have blood group A and AA (homozygous) and AO (heterozygous) and group B as BB or BO. However, group 0 can only exist genotypically as 00 in the homozygous recessive state.

(a) (i) Pollution; is the release of toxic or harmful substances into the environment by their natural forces or man and other animals to an extent that causes biological damage to man and his resources. (1) Pollutants of air are: Smoke, fumes, dust, harmful gases e.g sulphurdioxide, hydrogen sulphide, ammonia, chlorine/nitrogen oxides, carbon monoxide, pollen grains and soot. (2) Pollutants of water are: sewage, excreta/faeces, pesticides, chemical wastes/chemicals from factories, fertilizers, slurry/waste from farms, petroleum/ crude oil, heated water, oil spillage. (b)(i) Effects of water pollution on organisms are: (1) Destruction or death of valuable aquatic species such as sea birds, fishes e.t.c. (2) Food chain is affected, or disrupted. (3) Pollutants encourage bacterial growth leading to reduced amounts of dissolved oxygen/biological oxygen demand in water. This leads to death of fishes and other organisms. (4) Causes algae blood or putrification while water is rendered unsafe for domestic, drinking, industrial use or recreation. (5) It also leads to migration of water animals. (ii) Ways of preventing water pollution: (1) There should be efficient and proper sewage disposal system. (2) Dumping of refuse or petro-chemical by-products into rivers/streams/ponds or seas should be avoided. (3) The use of efficient techniques to deal with or prevent oil spillage should be adopted. (4) Industries should be sited away from residential areas and water bodies. (5) Government /local authorities should strictly monitor all industrial wastes and carry out public enlightenment. (6) Industrial effluents and hot water should be re-cycled. (c)(i) Sources of noise pollution are: (1) Factory or industrial noise. (2) Aeroplane/aviation noise (taking off and landing of aeroplanes). (3) Railway engine/locomotive noise. (4) Automobile/ car horns/sirens. (5) High pitched musical sounds from loud speakers/drumming. (6) Noise from mills/sawmills/ grinding mills/electronic gadgets and generators. (7) Artillary shots /shelling/canon shots. (8) Thunder noise. (ii) Effects of noise pollution on man: (1) Loss of hearing /deafening /hard hearing/hearing difficulty. (2) Emotional disorder/anxiety / fright and lack of concentration. (3) High blood pressure/hypertension. (4) General irritation/short temper. (5) Changes in behaviour.

(a) (i) Metamorphosis; refers to series of changes of forms or shapes from the fertilized egg (immature stage) to adult (mature stage or adulthood). (ii) Two types of metamorphosis are: Complete metamorphosis, e.g, Butterfly, Housefly, Bees, Wasp, Beetles, Mosquito and Incomplete metamorphosis, e.g, Grasshoppers, Cockroach, Dragonfly , Locust, Aphids, Termites, Praying mantis (b) (i) Economic importance of insects are: (1) Act as carriers, vectors or transmitters of diseases ( e.g anopheles mosquito, tsetsefly etc (2) Act as pests and are destructive to life plants or stored food (e.g locust; grasshoppers weevil, crickets) (3) As food or source of protein (e.g termites, honey, larval forms of some beetles, cricket, grasshopper) (4) Life processes involved in meiosis used in biological control (e.g lady bird - used in control of aphids on plantations, praying mantis:- control of some insects) (5) Serve as pollinating agents of flowering plants (e.g bees, butterflies, ants, moths, wasps, beetles). (6) Soil insects for aeration or loosening of soil (e.g termites, crickets, dung - beetles). (7) Insects as industrial material, (bee wax for candles, silk worms). (8) Termitarium used in building lawn tennis courts (9) Revenue yielding - e.g termites, larva of beetles e.t.c. (10) Destroy furniture, books, clothes, wood e.t.c, e.g cockroaches and termites. (ii) Peculiar features of social insects are: (1) They live together or form colonies (2) They live in nests. (3) Show or display division of labour. (4) Show distinct castes. (5) Members communicate with one another within the colonies.

(a) (i) Similarities found in plant and animal cells are: Cytoplasm, Nucleus, nucleolus, DNA, RNA, chromosomes, Cell membrane, Mitochondria, Golgi bodies, Endoplasmic reticulum, Nuclear membrane, Ribosomes. Types of human cells Functions Red blood cells/ corpuscles/ erythrocytes perform circulatory, excretory, respiratory or transport functions; carry O\(_2\) to or round the body and remove CO\(_2\) from cells. White blood cells/ leucocytes Defend, protect the body and provide immunity. Epidermal cells protect the body against disease germs, infection or dehydration Nerve cells/ spermatozoa for reproduction/ fertilization Nerve cells/ neurons Transmit impulses or messages from nerve fibres Ova/ eggs for reproduction muscle cells from muscles for movement or locomotion and attachment of bones and give shape to the body Bone cells / oesteoblast / oesteocytes Form bones, give support to or aid movement and give shape to the body Chondroblast/ cartilage Attachment of bones (support) Rods Photo receptor in dim light Cone Photo receptor in bright light (b) (i) The two types of cell divisions are Mitosis and Meiosis (ii)(a) Examples of life processes involved in mitosis are: Formation of new cells in the maiphigian layer of skin, Production of red blood cells and white blood cells in the bone marrow, Cell division in liver, Growth Spermatogenesis, Repair or healing of wound, Binary fission. (b) Examples of life processes involved in meiosis are: Formation of sperms (male gametes), Formation of oval eggs (female gametes), Formation of pollen grains in anther of flowering plants, Formation of ovules (in ovary) of flowering plants. (c) Two reproductive methods in organisms are: Sexual and Asexual