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Biology Paper 1


a) The science of classification;

b) A group of organisms that can freely/ naturally interbreed to give a fertile (viable ) off spring;

2 marks


Number of limbs;

Presence and number of antennae;

Number of body parts;

3 marks


a) Lactic acid;

b) Ethanol; Rej – alcohol

Carbon (iv) oxide;

ATP/ energy;

4 marks


a) Inconspicuous petals;

large anthers loosely attached to filament;

Long feathery stigma;

Small/ smooth and light pollen grains; (any three)

b) Brings about change in genetic materials which lead to variations that enable organisms to exploit new environment/ resistance to disease/ high yields in plants;

4 marks


a) Stores /contain hydrolytic enzymes to destruction of worn out organelles/cells tissues/ digestion of bacteria/ pathogens; Acc (-digestion of food/autolysis). b) Packaging /processing synthesized cell materials/production of lysosomes /secretion of packaged materials.acc (glycoprotein’s/mucus for packaged materials.)

2 marks


(Xylem)-transports water/mineral salts to different parts of the plant;

- Supports/ positions the leaf(lamina) in appropriate/suitable(position) for photosynthesis;

- Phloem- Translocates synthesized food/ organic food substances from the leaves to different parts of the plant; acc- specific parts.

3 marks


4 marks


a) Light energy;

b) The sun;

c) Chemichal engery

d) Lost in the form of heat through respiration/ faeces/urine;

3 marks


x - Carbon (iv) oxide (REJ Carbon dioxide)

y – Oxygen ;

b) Oxygen dissolves into ,moisture layer and diffuses across the thin epithelium of alveolus; then across the thin epithelium of capillary; combines with hemoglobin in red blood cells to form oxyhaemoglobin;

c) Medulla oblongata;

6 marks


a) Males are more mascular than females who have more fat;

b) Basal metabolic rate; Rej (BMR)

Occupation Body size;

4 marks


a) Gradual developmental changes from simple life to complex forms over a long period of time;

b) Variations arise by chance and from within the individual; through sexual reproduction these variations/characteristics are transmitted to successive offspring; some of the variations confer an advantage to individuals and are well suited/adapted survive selection pressure and survive;

Disadvantageous variations are poorly adapted and are eliminated; (2mks)

3 marks


a) Plants which are able to tolerate very salty conditions in soil/and marine water;

b) Have root cells which concentrate a lot of salts within to gain water by osmosis in the normal way; Some have salty gland that secrete excess salts; Most of them have water storage tissues;
Most submerged halophytes are found close to water surface where there is sufficient light for photosynthesis/Those deeper halophytes carry out photosynthesis under low light intensities;

3 marks


(a) Treponema palidum;
Herpes simplex;
(b) Where fertilization takes place;
Absorbs shock / acts as shock absorber / protects foetus against mechanical damage;

4 marks


(a) P, closed to prevent exhaled air from entering the tube A / when open allows exhaled air to enter into tube A;
Q, closed to prevent sucking in of the lime water;

(b) A- remains colourless showing less carbon (iv) in inspired air;
B-Lime water formed a white ppts showing exhaled air contains more carbon(iv) oxide;

4 marks


(i) Starch;

(ii) Glycogen;

2 marks


The cell sap is hypertonic to soil solution/ soil water; water is drawn into the root hair cell across the cell membrane; by osmosis;

3 marks


(a) (3) Incus ; rej-ear ossicless
(4) Auditory nerve;
(b) (5) Dispates/ cancels/ cushions excessive vibrations;
(7) Contains sensory cells when stimulated generates nerve impulses to the brain for interpretation/ integration;

4 marks


(a) enables plant roots to grow deep into the soil thus offering (firm) anchorage to the plants/absorption of water;

(b) enables pollen tubes to grow towards the embryo-sac to effect fertilization/sperms moving towards the ovum//anthropoids towards archegonia in ferns to; effect fertilization

3 marks


Single circulatory system the blood flows through the heart once for a complete circulation
while in double circulatory system blood flows through the heart twice for every complete
circulation; OWTTE.

1 marks


Chondrodystrophic dwarfness/achondroplasia;

1 marks



1 marks


(a) Loss of water from a plant in form of water vapour; (b )decrease in light intensity; Decrease/low

3 marks


(a) an increase in external environmental temperature (linearly) increases the body temperature of animal A;
(b) (i) poikilotherms/ excotherms;
(ii) Homoitherms/ endotherms;

3 marks


Through conversion into nitrates by nitrogen-fixing bacteria/rhizobium/Biotic fixation; Through
the action of lighting which combines atmospheric nitrogen into nitrates/A biotic fixation

2 marks


(I) Condensation; (B) sucrase;

2 marks


Magnify/enlarge image of objects/specimen;
To improve the resolving power/ show fine details of structures that are very close to
appear separate;

2 marks


Hydrogen carbonate ions; Carbonic acid

2 marks

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