Question Library

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

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

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

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

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

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

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

(a) A sense organ is a group of specialised cells or tissues and receptors, which is able to receive or collect, perceive and detect stimulus and transmit the information; impulse and message to the central nervous system. (b)(i)Two main functions of the ear are: Hearing and maintenance of balance. (ii) The mechanism involved in hearing are; The pinna; collects sound waves in the air, concentrates them and passes them on through the external auditor) canal or meatus. The waves; cause the tympanic membrane or ear drum to vibrate. The vibrations are passed on to the ear ossicles (mallens, inclus and stapes) which amplify them. The round oval window; fenestral oval is rotunda also vibrates, passing the waves into the cavity of the inner ear, cochlea, where the perilymph vibrates, transmits the waves in the cochlea which also causes the endolymph of the cochlea to vibrate. The vibrations are then transmitted across the organ of cot or sensory nerve cell or basilar membrane. The impulses; are set up and they stimulate the auditory nerve cells which then transmit the impulses to the brain, for interpretation. The mechanisms involved in the maintenance of balancing are as follows: Head movement in any direction affects the fluid or endolymphy, in the corresponding semicircular canals, which are at right angles to each other. This forces the sensory cells, gelatinous copula in the ampulla, to set up impulses through the auditory nerve to the brain and intern, for interpretation. The brain relays the impulses to the body muscles, for balancing/ determine the position of the body.

(a) Different methods used in Vegetative Propagation are: (i) Use of modified underground sterns e.g. cocoyam, corn, sucker, etc. (ii) Cutting of stem with two or three nodes and buds, e.g. cassava, croton, hibiscus, Ixora (sweet potato) (iii) Flesh leaves e.g. onion, Bryophyllum/ bubuks (iv) Budding: a dormant bud from one plant/ scion, e.g., citrus, mango. (v) Grafting, where part of one plant is joined to another of the same or related species, e.g., citrus,mango. (vi) Layering: A branch close to the soil is bent so that part of the branch touches the soil. The end of the branch is then tied to a firm support. A ring of bark has to be removed from the part of the branch touching the soil while a slit is made half way through the branch. Then this part has to be pushed below the soil and cover with soil while a heavy object is placed on the heap of the soil to weigh it down, e.g., Bougainvillea, Rose plant (sp) cocoa, coffee. (vii) Marcoting, e.g. mango, lemon (citrus), Rose (Rosa sp) (b)(i) Advantages of Vegetative propagation are: young plant uses food reserves of the parent as it becomes established or easily established. Growth in young plant is rapid since there is no resting or lag period Only one parent is needed desirable characters are retained offspring is identical to parent offspring matures more rapidly are less susceptible to adverse weather conditions plants that do not produce seeds can only be [propagated vegetatively) (ii) Disadvantages of vegetative propagation are: No new varieties are produced; no mixing of characters offspring and parents compete for light and nutrients since many individuals occupy a limited area of land overcrowding; reduces resistance to disease reduces resistance to changes in climate / adaptation to environment. colonisation of new localities unlikely, since offspring is always produced close to parent plant diseases of parents will be transmitted to offspring undesirable features are easily transmitted to offspring.

(a) Classes of food other than carbohydrates are: protein, fats and oils / lipids, water, vitamins, mineral salts. (b) The reasons why glucose is taken by an athlete before a race are: glucose is the simplest form of carbohydrate, i.e. soluble form of cabohydrate; which does not require any form of digestion. Hence, it is absorbed in the ileum, small intestine, where it diffuses and enters into the blood stream, circulatory system. It is then assimilated and oxidized; within the shortest time to give energy to the athlete. But corn meal is a complex carbohydrate, polysaccharide, starch, which will require series of carbohydrate / hyrolysis, starting from the mouth and later in the duodenum. Due to the processes, carbohydrate has to pass through it to the small intestine, ileum, which takes a longer time to produce energy for use, i.e cannot give immediate energy. (c) To test for starch, obtain tuber of yam, cassava, potato, sweet potato, maize, cereal or any starchy food and macerate (crush). Then, add water to the mash to prepare starch solution; put a few drops of the starch (mashed material or a bit of the macerate on a white tile) test tube or watch glass. Add one to two drops of iodine and the material or solution will turn blue black, or black indicating presence of starch.

(a)(i) The four levels of organisation in living: organisms are: Cell, tissue, organ, system (ii) A cell is a basic structural and function unit of life; it is bounded by a membrane containing nucleus and cytoplasm. Some cells are capable of independent existence, carrying out all the characteristics or life processes in living things. They may have processes like pseudopodia, cilia, flagella, etc. Cells also have inclusions, referred to as organales. A tissue is a collection of cells which are similar in structure and perform similar functions. Some tissues cannot exist on their own but some can live on their own, e.a., Hydra. They have the same origin and occupy the same position in the body of the organism. An organ is a collection of different tissues that perform a common function or functions. Some organs carry out a single function. e.g., heart while others carry our more than one function, e.g., kidney. A system; is made up of different organs that perform a particular function. Systems are peculiar to higher organisms.

(a) Features: Sun, cloud, plant, animal ground / earth / soil and river/ water/ body/ sea/ lake/ stream/ ocean. Processes with corresponding arrows: Precipitation / condensation in clouds; - Evaporation of water from water body, river, sea Evaporation of water from soil or ground; Excretion by animal; Drinking by animals; Perspiration and respiration by animals; Absorption of water by roots; Transpiration by plants; Erosion or run-off water from soil; Respiration in plants; Decay in plants. (b) Importance of water in living organisms are: General: (i) Life started in water (ii) Some organisms still live in water. (iii) All organisms contain at least 50% of water (iv) Biochemical reactions occur in aqueous medium organisms, e.g.; gaseous exchange, digestion and absorption. (v) It serves as food. (vi) It increases for the growth of organisms. (ii) Transport Medium: (Blood plasma / tissue fluid/ lymph: (i) for excretory products; - hormones (ii) for end products of digestion. (iii) dispersal of larval stages of aquatic amphibians (iv) transfer of gauntest of mosses, ferns and some animals (v) dispersal of some seeds. Solvent: (I) Removal of excretory products, ammonia and urea. (ii) Component of secretions, digestive juices, tears and venom in snakes. Lubricant: (i) mucus for external at movement in snails and earthworms (ii) for internal movement in the gut and vagina (iii) Perivisceral fluid in the fe viscera. Support: (i) Amniotic fluid in mammals (ii) vitreous/ aqueous humour of the mammalian eye, tutor pressure m in the herbaceous plants (iii) erection of penis (iv) hemocoel in earthworms. Miscellaneous: (i) temperature control through sweating, panting and transpiration (ii) endolymph and perilymph in the mammalian ear.

(a) Osmosis is the process by which water molecules or solvent move from area or region of weaker solution through a semi-permeable membrane. It can also be defined as the movement of water or water molecules from a region of higher concentration of water molecules to a region of weaker concentration of water molecules through a semi-permeable membrane. (b) A young herbaceous plant, balsom or water plant, is uprooted. The roots are washed with water to remove the soil particles. Expose the set-up to sunlight and allow it to stand for about one to six hours. Remove the plant and wash the roots thoroughly and make transverse sections of the root, stem and leaf. Then, observe the sections under the microscope or hand lens. It will be observed that only the xylem tissue picks the colour of the dye and will be stained red, indicating that water moves through xylem tissues. (c)(i) When a red blood cell is placed in hypotonic or weaker solution, water enters the red blood cell by osmosis through the cell membrane which serves as a semi-permeable membrane. Continuous gain or absorption of water by the red blood cell makes the cell swell or enlarge in size and eventually burst. Hence hemolyses or heamolysis takes place. (b (ii) Three conditions that may cause heamolysis are: (1) disease attack (2) abuse or use of drugs and food (3) poisoning (4) infection/ epidemic (5) industrial activities/ pollution.

Let the three items be M, Y and P. n{M ∩ Y} only = 4-3 = 1 n{M ∩ P) only = 5-3 = 2 n{ Y ∩ P} only = 2 n{M} only = 12-(1+3+2) = 6 n{Y} only = 10-(1+2+3) = 4 n{P} only = 14-(2+3+2) = 7 n{M∩P∩Y} = 3 Number of women in the group = 6+4+7+(1+2+2+3) as above =25 women.

\(log_810\) = X = \(log_8{2 x 5}\) \(log_82\) + \(log_85\) = X Base 8 can be written as \(2^3\) \(log_82 = y\) therefore \(2 = 8^y\) \(y = \frac{1}{3}\) \(\frac{1}{3} = log_82\) taking \(\frac{1}{3}\) to the other side of the original equation \(log_85 = X-\frac{1}{3}\) explanation courtesy of Oluteyu and Ifechuks OR Given \(\log_8 10 = X\), we can express \(\log_8 5\) as follows: \(\log_8 5 = \log_8 \left( \frac{10}{2} \right) = \log_8 10 - \log_8 2\) Using the change of base formula, we find: \(\log_8 2 = \frac{\log 2}{\log 8} = \frac{1}{3}\) Thus, substituting back, we get: \(\log_8 5 = X - \log_8 2 = X - \frac{1}{3}\)