In an experiment, students treated seedlings as illustrated below.

​(i) Account for the observations made in seedling I. 
(ii) Explain the similarity in the end results made in seedlings II and III. 
(iii) State the likely treatment that would make seedlings II and III respond like seedling I.

In an experiment to investigate the effect of sodium chloride on the growth rate in a spinach seedling, seeds were treated with different concentrations of sodium chloride. The results are as recorded in the table below.

​(a) From the results in the table above, explain the effect of increasing the concentration of sodium chloride. 
(b) Apart from a ruler, state two other equipment one would need to determine the rate of growth in the roots. 
(c) With a reason, state one other part of the seedling the students would focus on to determine the effect of sodium chloride on growth. 
(d) State the likely effect on the seedling of increasing the concentration of sodium chloride to 2.20mol/l

The effect of auxin concentration on growth response of two parts of a plant, X and Y was investigated over a period of time. The results were tabulated as shown in the table below.

(a) On the same axis, draw line graphs of the effect on growth of the two parts, X and Y (percentage inhibition or stimulation) against the concentration 
(b) With reasons, name the two parts of the plant, X and Y.
X 
Reason 
Y
Reason
(c) From the graph identify: .
(i) the point at which the percentage stimulation was the same for both X and Y. 
(ii) the optimum concentration of auxins required for part Y 
(d) State three ways in which the effects of auxins on plants is applied in flower farming.
(e) Distinguish between simple and conditioned reflex action 

State two characteristics of living things illustrated in the photograph below.

The diagram below illustrates a germinating seedling.

​(a) Name the type of germination illustrated in the diagram
 (b) Describe how the type of germination named in (a) above is brought about.

The photograph below illustrates a germinating seedling.

​(a) Name the type of germination illustrated in the photograph. 
(b) Explain the function of each of the parts labelled G and H.
G 
H 

The photograph illustrates a housefly at various stages of its development.

​(a) (i) On the photograph, name the stages of the life cycle. 
(ii) Using arrows, link the stages of the life cycle in the correct order. 
(b) (i) State two differences between the life cycles of a housefly and that of a cockroach. 
(ii) State one advantage of the life cycle of a cockroach to itself.

K.C.S.E Biology Q & A - MODEL 2016PP1QN015

K.C.S.E Biology Q & A - MODEL 2016PP1QN15

(a) Using the axes provided below, sketch a curve to illustrate the growth pattern observed in the phylum arthropoda.

(b) Explain the growth pattern observed observed in arthropods.

The diagram below shows an experimental set-up to investigate the conditions necessary for germination. Test tube P was placed in a refrigerator while Q was left at room temperature. The set-ups were observed regularly for two weeks but no germination occurred.

​Explain the observations in P and Q.
P 
Q

K.C.S.E Biology Q & A - MODEL 2014PP1QN02

K.C.S.E Biology Q & A - MODEL 2014PP1QN02

K.C.S.E Biology Q & A - MODEL 2013PP1QN19

State the role of the following hormones in the life cycle of insects: 
ecdysone hormone; .
juvenile hormone.