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Let the number of students that offer both subject be x hence, the number of students offering physics = 3x The number of students offering chemistry = 6x The number of students offering physics only = 3x - x = 2x The number of students offering chemistry only = 6x - x = 5x So, 2x + 5x + x = 40 8x = 40 x = \(\frac{40}{8}\) = 5. Therefore, the number of students offering physics only = 2x = 2 x 5 = 10.

Protective adaptations used by animals against predation (i) Mechanical protection like the hard outer covering/ shell; e.g. giant snail/tortoise/oysters/barnacles/battery of spines in porcupine/sea urchin (ii) Chemical protection in the form of poisonous secretions of skin glands; e.g. toad (iii) Concealing colouration/cryptic adaptation/a close matching in appearance of the animal to its background; e.g. chameleon/praying mantis/green mamba (iv) Specialised toxic glands/hairs linked to toxic glands/hairs that penetrate skin of predators/toxin secreted to cause intense irritation; e.g. larvae of Lepidoptera (v) Mimicry of objects such as leaves or twigs; e.g. Praying mantis/stick insect/ moths (vi) Rolling the body into a ball; e.g. pangolin/millipede/porcupine (vii) Fast movement to escape from enemies; e.g. antelopes/deers (viii) Secretion of offensive smell; e.g. shrews/zonocerus (ix) Stings/injection of painful chemicals; e.g. bees/wasps/scorpions/electric fish (x) Offensive structures of horns/hooves; e.g. antelopes/gazel/buffalos (xi) Movement in groups to frighten predators; e.g. monkeys/baboons/small angulates (xii) Detachment/dropping of parts of the body to escape; e.g. lizards/wall geckos (xiii) Secretion of ink/coloured substance to impair vision of predator/create a screen e.g. squid (xiv) Inflation of the body to frighten predator; e.g. chameleon/octopus/cats (xv) And any other correct adaptive features and correct examples (b)(i) Pollution (a) The introduction of materials/ energy into the environment by humans (directly or indirectly) (b) at such levels/concentration that affect biotic communities adversely thereby causing harm (ii)Activities of humans which cause pollution (a) Dumping of domestic/ farm refuse (b) Release of chemicals from mines (c) Misapplication of agro chemicals/fertilizers (d) Spraying of pesticides and herbicides (e) Dumping of broken bottles/glasses/ enamel wares (f) Dumping of plastics (g) Dumping of scrap metals (h) Spillage of crude oil from pipelines/tankers (i) Dumping of untreated sewage (j) Effluent from factories/breweries/laboratories (i) Any other correct human activity

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

(a) A habitat is a type of environment/a place/an area, in which plants and animals/organisms live or an area/place/ environment; occupied by a biotic community/organisms (b) Energy flow in freshwater habitat is as follows: (i) energy from sun/radiant energy/solar energy is received. (ii) It is then absorbed/trapped by green plants/algae/ phytoplanking (of fresh water/pond/stream/river etc) (iii) This is used in photosynthesis/to synthesize/manufacture organic substances (iv) Zooplankion/fish/animals of the pond would now depend or feed on the green plants for food (v) The feeding is direct if they are herbivores as the plants are eaten by herbivores (vi) The feeding is indirect if they are carnivores as herbivores are eaten by carnivores (vii) when plants or animals/organisms die or when animals discharge their droppings/wastes, they are decomposed via the action of saprophytes/fungi/bacteria decomposers/ micro-organisms (viii) By sodaing, energy is lost (c)(i) Biotic Factors; (a) plants/producers (b) animals/consumers (c) parasites (d) decomposers/saprophytes/micro-organisms (e) predators (ii) Abiotic Factors; (a) temperature (b) sunlight/light (c) wind (d) inorganic compounds (e) turbidity/suspended particles/transparency (f) topography (g) dissolved oxygen (h) pH/dissolved CO2 (i) water currents/currents (i) rainfall/precipitation

(a)(i) A joint is a point/place, where two or more bones meet/articulate in the body (ii) Types of Joints Location in the Body - Ball and socket joint -Shoulder/hip -Hinge joint -Elbow/knee/phalanges -Sliding/gliding joint - Wrist/ankle/vertebrae -Pivot/rotating joint - Neck (ii) Adaptation of structure to function; (a) There is the presence of cartilage to reduce friction between 2 bones in contact (b) Ligament holds the bones together (c) Synovial membrane secretes the synovial fluid (d) Synovial fluid lubricates the joint thereby minimize shock and friction leading to easy movement of joint.

(a) Pollination and Fertilization; (i) Whereas pollination is the transfer of pollen grains from the anther of a flower to the stigma of a flower; fertilization is the fusion of the male gamete/nucleus, with that of the female gamete/nucleus; to form a zygote (ii) Pollination precedes fertilization (b) Features that ensure cross pollination and Examples; (i) Dioecious plants/male and female flowers occur on separate plants e.g. pawpaw/ any correct example. (ii) Dichogamy/Male and female parts mature at different times (iii) Phragmanthera/ mistletoe; is protogynous/protandry/carpels mature before Stamens (thus separating. the reproductive structure in time) sun flower/cotton is protandrous/ stamen, mature before carpel. Crotolaria examples of ptologynous plant. Male and female parts are of different lengths/heterostyly/long style and short stamen e.g. Morinda. Moneocious plants/Male and female flowers occur on the same plant in different position e.g. Maize/Luffa/Oil palm/coconut etc (male flower at the apex matures first whereas the female flower in the axil of leaves matures later) the feathery stigma hang loosely and can catch airborne pollen grains but not from the same flower. Structure: Most flowers are so structured as to prevent self pollination since only a particular insect/animal can effect pollination; e.g. Crotalaria/CentrocemaNigna/pea/groundnut- stamens mature first shedding pollen into a sac-like tube formed by the keel honey guides on the standard which direct the bee to the sectaries and the stigma points towards entrance of keel and can only receive pollen brought in by a visiting bee. Self-incompatibility/self-sterility (certain chemicals on the surface of the stigma prevent growth in pollen tubes; of pollen grains from the same flower) e.g. Clover. Possession of brightly coloured petals attract insects e.g. Delonix, Hibiscus. Sweet smell for attraction of insects e.g. Rose flower. (c)(i) Agents of pollination are as follows (a) Insect/bat/animal/any named animal (b) Wind/Air (c) Water (ii) Features of wind dispersed fruits/ seeds (a) Seeds are almost always with floss thereby aiding its ability to be flown or be airborne. (b) Winged seeds/fruits (c) Light-weight seeds/fruits (d) Parachute/hairs.

(a) Experiment to show that green plants require sunlight for photosynthesis; (i) Take two potted plants and get them well watered (ii) De-starch the leaves by keeping plants in a dark cupboard 'at least for 24 hours/overnight (iii) Then test leaf samples of both plants for starch (iv) The result is negative/yellowish-brown colour which shows absence of starch (v) Leave one potted plant in the dark cupboard as a control and put the other plant in sunlight for 4-6 hours (vi) Re-test leaves from both plants for starch. You will discover that (vii) leaves from plant exposed to sunlight show presence of starch, while those from the control plant/kept in dark cupboard shows absence of starch (viii) This indicates that sunlight is necessary for photosynthesis. (b) Other conditions necessary for photosynthesis include the following: (i) Presence of water (ii) carbon dioxide (iii) chlorophyll/chloroplast (vi) suitable temperature (c) Site or part of dicotyledonous leaf where photosynthesis occurs is the palisade layer; because it contains more chloroplasts/chlorophyll; than the spongy layer/other parts. Palisade cells are located just beneath the upper epidermis; where the chlorophyll could absorb more sunlight (d) Fate of food manufactured by green plants: (i) Manufactured food/glucose; is trans-located to various parts of the plant through the phloem (ii) This can be combined with other elements such as nitrogen and sulphur to form proteins; for growth. It can also be converted to starch and stored. It is needed/used in respiration/metabolic activities. It is broken down into carbon dioxide and water to produce energy. Other products like lipids and cellulose can also be manufactured from glucose.

(a)(i) Phenotype is the external appearance of an organism resulting from the interaction between the genotype and the environment (ii) A hybrid is the offspring/progeny from a cross between two organisms/parents, which are genotypically different/having unlike traits/character (iii) Dominant character is the feature/trait expressed by the hybrid/offspring/progeny, in the presence of its alternative form. (c) Benefits of genetics in agriculture. (i) It promotes cross breeding to produce offsprings of superior characters/hybrid vigour (ii) It enhances animal/crop selection to obtain varieties of animals/crops with qualities such as early maturity higher yield, resistance to diseases (iii) It leads to the development of genetic engineering which introduce genes of desired trait/character into an organism (iv) In-breeding of desirable strains to obtain pure breed.

To evaluate the expression \( \log_{\sqrt{2}} 4 + \log_{\frac{1}{2}} 16 - \log_{4} 32 \), we can simplify each term separately. 1. Calculate \( \log_{\sqrt{2}} 4 \) \(\log_{\sqrt{2}} 4 = \frac{\log_2 4}{\log_2 \sqrt{2}}\) We know that \( \log_2 4 = 2 \) (since \( 2^2 = 4 \)) and \( \log_2 \sqrt{2} = \log_2 2^{1/2} = \frac{1}{2} \). Thus, \(log_{\sqrt{2}} 4 = \frac{2}{\frac{1}{2}} = 4\) 2. Calculate \( \log_{\frac{1}{2}} 16 \) \(\log_{\frac{1}{2}} 16 = \frac{\log_2 16}{\log_2 \frac{1}{2}}\) We know that \( \log_2 16 = 4 \) (since \( 2^4 = 16 \)) and \( \log_2 \frac{1}{2} = \log_2 2^{-1} = -1 \). Thus, \(\log_{\frac{1}{2}} 16 = \frac{4}{-1} = -4\) 3. Calculate \( \log_{4} 32 \) \(\log_{4} 32 = \frac{\log_2 32}{\log_2 4}\) We know that \( \log_2 32 = 5 \) (since \( 2^5 = 32 \)) and \( \log_2 4 = 2 \). Thus, \(\log_{4} 32 = \frac{5}{2}\) Now, we can substitute these results back into the original expression: \(\log_{\sqrt{2}} 4 + \log_{\frac{1}{2}} 16 - \log_{4} 32 = 4 - 4 - \frac{5}{2}\) Calculating this gives: \(4 - 4 - \frac{5}{2} = 0 - \frac{5}{2} = -\frac{5}{2}\) Thus, the final result is: \(-\frac{5}{2}\) = - 2.5

You can either multiply directly in base 4 or you can decide to convert to base 10 and do the multiplication and re-convert.

Using a venn diagram, let x = number who offer both Maths and Physics. So that (32-x) offer Maths and another (24-x) offer Physics. (32-x) + (24-x) + (x) + (4 who offer neither) = 40 => 60 - x = 40 => -x = -20 Therefore x = 20.

\((\frac{1}{0.06} \div \frac{1}{0.042})^{-1}\) = \((\frac{100}{6} \div \frac{1000}{42})^{-1}\) = \((\frac{100}{6} \times \frac{42}{1000})^{-1}\) = \((\frac{7}{10})^{-1}\) = \(\frac{10}{7}\) = 1.4285 \(\approxeq\) 1.43.

C.P = N1800 S.P = (270/5) x 40 = N2160.00 Profit = S.P - C.P = N2160 - N1800 = N360.00

\(1 - (\frac{7}{3} \times \frac{5}{4}) + \frac{3}{5}\) = \(1 - \frac{35}{12} + \frac{3}{5}\) = \(\frac{60 - 175 + 36}{60}\) = \(\frac{-79}{60}\)

\(\frac{\sqrt{98} - \sqrt{50}}{\sqrt{32}}\) = \(\frac{\sqrt{49 \times 2} - \sqrt{25 \times 2}}{\sqrt{16 \times 2}}\) => \(\frac{7\sqrt{2} - 5\sqrt{2}}{4\sqrt{2}}\) = \(\frac{2\sqrt{2}}{4\sqrt{2}}\) = \(\frac{1}{2}\)