Question 1 |
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The diagram below is an illustration of the reproductive system of a mammal. Study the diagram and use it to answer questions (a) and (b)
(ii) Name the parts labelled I-X. [5 marks] (iii) State one function each of the parts labelled I, IV, V, VI and X. [5 marks] (b) (i) Explain briefly how the part labelled VIII is adapted to life. [6 marks] (ii) Describe briefly the process in humans that gives rise to the formation of the part labelled VIII. [8 marks] |
ANSWER
1(a) (i) Identification of structure A mammalian/human embryo/foetus in the womb
(ii) Label of parts
I. Placenta
II. Chorion
III. Amnion
IV. Amniotic fluid
V. Vagina/birth canal
VI. Cervix
VII. Uterus/womb/uterine wall
VIII. Embryo/foetus
IX. Umbilical cord
X. Fallopian tube/Oviduct
(iii) Functions of parts labelled I, IV, V, VI and X
I – Exchange of materials between mother and embryo;
IV – Protects the embryo from shock/damage
V – Opening for passage of sperms into the female/delivery of the foetus.
VI – A gateway to the uterus/womb/for passage of sperm/blood/secretes mucus to keep the vagina lubricated/allows passage of foetus.
X – Site for fertilization/receives matured egg/ovum/passage of egg into the uterus.
(b) (i) Adaptation of part labelled VIII/embryo to life The embryo is adapted to life by the placenta; a structure that allows the embryo to remove waste products; through the mother at the same time obtain oxygen; water and digested food/antibodies; presence of amniotic fluid; serves as shock absorber/protects it against injury/damage; highly vascularized umbilical cord; that connects mother to foetus to promote exchange of materials. Note: Structure and function must tally to score.
(ii) Process that leads to formation of part labelled VIII/Embryo/Foetus The process by which the embryo is formed is sexual reproduction; during mating; the male human introduces the erect penis into vagina of a female human; thereby ejaculates/releases sperms into the vagina; sperms swim to the uterus through the cervix; then into the oviduct/fallopian tube to meet a matured egg; which has been released from the ovary/ovulation occurs; sperm(s) fertilize(s) the egg/ovum to form a zygote; which migrates to the womb/uterus; becomes and gets implanted onto the inner lining of the uterus; This develops into the structure labelled VIII/embryo/foetus.
Question 2 |
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The diagram below is an illustration of a biotic community. Study it carefully and use it to answer questions 2(a) to 2(d).
(a) (i) Name the biotic community represented in the diagram. [1 mark] (b) (i) State five abiotic factors that can influence the biotic community named in 2 (a) (i).[5 marks] (c) (i) State two effects of rainfall on the community. [2 marks] (d) (i) State two characteristic features each of the plant and animal mentioned in 2 (c) (ii). [4 marks] |
ANSWER
(a) (i) Name of Community Guinea Savanna/ Savanna/Savannah
(ii) Characteristic features of community Plenty grass; scattered/few trees; trees with broad crowns; many herbivores/rodents/named herbivore/carnivore/named carnivore, Guinea fowl, grasshopper.
(b) (i) Abiotic factors Rainfall; humidity; temperature; atmospheric pressure; wind; light intensity/sunlight; pH; Soil/Edaphic factors.
(ii) Instruments Rain gauge, hygrometer, thermometer, barometer, anemometer, wind vane, pH meter, light meter/photometer.
(c) (i) Effects of rainfall
– when there is sufficient rainfall grasses grow taller; plenty grass and animals will abound;
– heavy rainfall leads to soil erosion/leaching/flooding;
– when there is scarcity of rainfall grasses dry up/wither and die;
– the animals emigrate/disperse/may die/aestivate.
(ii) Name of plant and animal
Plant: Grasses/ Elephant grass/Imperata/Guinea grass.
Animal: Lion/Hyena/Cheetah/Tiger/Leopard/Praying mantis/Spider/Snake
(d) (i) Characteristic features of plant and animal
Plant: turfted; underground stems; leaves have thick cuticle and sunken stomata
Animal: Presence of canine; good sense of smell/sight/hearing; strong jaws/mandibles; sharp claws/ muscular/powerful/strong limbs/legs.
(ii) Adaptations
Plant: Small leaves to reduce transpiration; underground stem for quick re-growth after fire/drought.
Animal: Muscular legs to run fast; strongly built for agility and speed; long canines and claws to grasp prey/ good sense of smell/sight/hearing to sight prey.
NOT
(a) The Table below shows parts of the alimentary canals possessed by different animals. Tick (?) the part possessed by the corresponding animal in the Table.
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Animal | Parts of alimentary canal | |||||
Pharynx | Gullet | Crop | Stomach | Caecum | Rectum | ||
1. | Planaria |
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2. | Earthworm |
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3. | Cockroach |
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4. | Tilapia |
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5. | Frog |
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6. | Lizard |
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7. | Bird |
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8. | Rabbit |
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9. | Cow |
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10. | Human |
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[17 marks]
(b) (i) State five functions of the stomach in humans. [5 marks]
(ii) Explain briefly the stages of holozoic nutrition in humans. [5 marks]
(c) State three effects of indigestion in humans. [3 marks]
ANSWER
(b) (i) Functions of stomach of Humans
– The stomach temporarily stores food;
– stomach secretes gastric juice containing hydrochloric acid; pepsin and rennin;
– hydrochloric acid provides acidic medium for protein digestion;
– hydrochloric acid destroys harmful bacteria in the stomach;
– rennin solidifies /curdles milk;
– pepsin digests protein into peptides in the stomach
– large particles of food are turned and broken down to smaller particles by the contraction of the stomach muscle/churning.
(ii) Stages of holozoic nutrition
Ingestion; taking in pieces of solid food into the mouth
Digestion: breaking down of large food particles by mechanical/chewing; enzymatic activites/chemical means into smaller particles/soluble that the body can absorb.
Absorption: taking up the soluble products of digestion into the blood;
Assimilation: using/utilization of the absorbed food materials by the body cells/tissues; Egestion: elimination of the undigested food materials through the anus.
(c) Effects of indigestion in humans
– causes constipation/inability to defaecate;
– bloated stomach;
– stomach ache;
– heartburn/burning sensation;
– general weakness;
– flatulence/release of gas.
