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1. 1989 Q2 P1
State one structural and one functional difference between motor and sensory neurons. 2. 1990 Q15 P1 (a) How are the structures of the human eye adapted to their function?
1. 1989 Q6 P1
The diagram below represents a mammalian bone 
(a) State the functions labelled K and L
(b) State the region of the body in which the bone is found 2. 1991 Q1 P1 State two ways in which skeletal muscle fibers are adapted to their functions 3. 1991 Q5 P1 The diagram below shows the arrangement of bones and muscles in a human arm K.C.S.E Biology Q & A - MODEL 2019PP2QN05
A person accidentally touches a hot pan and responds as illustrated in the diagram below.
(a) Explain how the response illustrated above occurs.
(b) Explain how auxins are utilised as selective weed killers in agriculture.
answers
K.C.S.E Biology Q & A - MODEL 2019PP2QN04
In cats, the gene for fur colour is sex-linked. Letter G represents the gene for ginger fur colour while letter B represents the gene for black fur colour in a given cat species. These genes are co-dominant. Heterozygous females have ginger and black patches of fur and their phenotype is described as tortoise-shell.
​(a) With reference to the information given above, what is meant by the term co-dominance?
(b) Explain why male cats with a tortoise-shell phenotype do not usually occur. (c) A tortoise-shell female was crossed with a black male. Determine the genotypes and phenotypes of the offspring.
answers
K.C.S.E Biology Q & A - MODEL 2019PP1QN25
State one characteristic of muscles responsible for each of the following:
(a) peristaltic movement (b) movement of limbs
answers
​(a) spindle shape
Lack striations/ not striated Uninucleated /one nucleus (b) striated; Numerous mitochondrion; Multinucleated/many nucleus Cylindrical shaped.
K.C.S.E Biology Q & A - MODEL 2019PP1QN24
Explain the evolutionary basis for the ever changing drugs for malaria treatment.
answers
K.C.S.E Biology Q & A - MODEL 2019PP1QN17
Below are photographs of two dogs.
​Explain the possible reason for the difference in the length of their fur.
answers
K.C.S.E Biology Q & A - MODEL 2019PP1QN14
Name the evidence of organic evolution exhibited by occurrence of similar amino acid molecules in a range of organisms.
answers
(b) comparative physiology/ biochemistry/cell biology;
Acc. Serology /comparative serology.
K.C.S.E Biology Q & A - MODEL 2019PP1QN14
Explain why fossil records as evidence of organic evolution are usually incomplete.
answers
(a) partial/ entire decomposition of dead organisms/ organic matter;
Some parts of or entire dead organisms are eaten by scavengers; Soft bodied organisms do not fertilize; Destruction of parts due to natural disasters, like earthquakes/earth movements like, faulting /folding/ volcanicity/ mass movement; Distortion of parts of an organism due to sedimentary/ faulting/folding/volcanic K.C.S.E Biology Q & A - MODEL 2019PP1QN10
In an investigation, students set up the apparatus below in the laboratory and made observations after 72 hours.
​(a) Explain how inclusion of the following components would affect the mouse in the experiment:
(i) light (ii) sodium hydroxide solution (b) State why the students preferred to use a bell jar and not a tin box in the experiment.
answers
​.(a) i) light enables the potted plant to photosynthesize; producing oxygen which is
Inhaled by the mouse, (sustaining it); the illuminated light can further affect /alter some photosynthesized processes in the mouse as a result of constant direct beam of light. (ii) Absorbs carbon(iv)oxide (mainly exhaled by the mouse); while at the same time deny the plant the needed raw material, carbon (iv) oxide to photosynthesize hence suffocating the mouse/ emitting its survival / no oxygen; (b) bell jar is transparent, allow penetration of light for the plant to photosynthesize; tin box is opaque hence does not allow photosynthesis/ could easily heat up altering the temperature inside for the mouse/ plant; K.C.S.E Biology Q & A - MODEL 2018PP2QN04
The diagram below illustrates the arrangement of bones in a human arm.
​(a) Name:
(i) the type of joints formed at points H and M. H M (ii) bone G (b) Name bone J and state how it is adapted to its functions. Name Adaptation (c) State one functional difference between a tendon and a ligament.
answers
​a) i. H-Ball and socket (joint);
M - Gliding/planar/plane ii. Clavicle; b) Scapula; Has a spine to increase surface area for muscle attachment; It is broad/flat to increase the surface area for muscle attachment; Forms flexible attachment above the ribs that allows movement of the arms; Has a glenoid cavity/depression for articulation with the humerus/forming the ball and socket joint; Has acromion for articulation with clavicle/for muscle attachment; Has coracoid process to increase surface area for muscle attachment; c) Ligaments hold the bones together (at a joint) while tendons attach muscles to bones; K.C.S.E Biology Q & A - MODEL 2018PP2QN03
The amount of blood flowing tough certain pans in the mammalian body at different activity levels was measured and results tabulated as Shows in the table below.
​(a) Account for:
(i) the high blood flow through the cardiac and skeletal muscles during strenuous exercises. (ii) the results obtained for the alimentary canal at rest. (b)Name two waste materials excreted by both the skin and the kidneys.
answers
K.C.S.E Biology Q & A - MODEL 2018PP1QN25
Desert kangaroo rats spend most of their time in underground burrows,
(a) Name this type of behavioral activity (b) Explain the significance of this behaviour to the organism.
answers
​(a) Aestivation;
(b) Reduced metabolic activity; hence low rate of respiration; minimizing water loss/dessication (to the environment);
K.C.S.E Biology Q & A - MODEL 2018PP1QN22
What does the term evolution mean?
answers
K.C.S.E Biology Q & A - MODEL 2018PP1QN21
State two ways in which plants with weak stems obtain mechanical support.
answers
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