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a) Iris.
b) Circular muscles relax; radial muscles contract widening the pupil.
c) Adjustment of the eye structure to bring an image from a near or far object into sharp focus on the retina.
marto answered the question on October 7, 2019 at 11:37
- State three limitations of fossils records as an evidence of organic evolution.(Solved)
State three limitations of fossils records as an evidence of organic evolution.
Date posted: October 7, 2019. Answers (1)
- Name the region of the gut where digestion of cellulose takes place.(Solved)
Name the region of the gut where digestion of cellulose takes place.
Date posted: October 7, 2019. Answers (1)
- The table below is a representation of a chromatide with genes along its length. It undergoes mutation to appear as shown below.(Solved)
The table below is a representation of a chromatide with genes along its length. It undergoes mutation to appear as shown below.
a) Name the type of chromosomal mutation represented.
b) Name one mutagenic agent.
Date posted: October 7, 2019. Answers (1)
- Wekesa and Wanjiku who are siblings are both normal as their parents but have a hemophilic
brother. Give the Genotype of their parents.
i)What are linked...(Solved)
Wekesa and Wanjiku who are siblings are both normal as their parents but have a hemophilic
brother. Give the Genotype of their parents.
i)What are linked genes?
ii) What do you understand by the phase a test cross
Date posted: October 7, 2019. Answers (1)
- The figure below represents the distribution of height of pupils in a school.(Solved)
The figure below represents the distribution of height of pupils in a school.
(a) Name the type of variation represented by the curve
(b) Outline two possible causes of variation in height of individuals in man
Date posted: October 7, 2019. Answers (1)
- Distinguish between complete and incomplete dominance.(Solved)
Distinguish between complete and incomplete dominance.
Date posted: October 7, 2019. Answers (1)
- In an experiment the radicle of a seedling was marked equidistant using Indian ink as shown in the diagram below.(Solved)
In an experiment the radicle of a seedling was marked equidistant using Indian ink as shown in the diagram below.
(a) What was the aim of the experiment?
(b) On the diagram below mark on the radicle to show the appearance of the marks after 3days
(c ) State three characteristics of cells found just behind the root cap of a radicle
(d) Give two factors inside a seed that causes seed dormancy
Date posted: October 7, 2019. Answers (1)
- Give the form in which each of the following substances are transported in mammalian blood:(i) Carbon (IV) oxide(ii) Oxygen(Solved)
Give the form in which each of the following substances are transported in mammalian blood:(i) Carbon (IV) oxide(ii) Oxygen
Date posted: October 7, 2019. Answers (1)
- Carefully study the figure below and answer the questions that follow:-(Solved)
Carefully study the figure below and answer the questions that follow:-
The seedling with straight radicle and plumule was attached to a machine horizontally as shown above. The machine rotates making one revolution in 15 minutes.
(a) Draw how the seedling would look like after one week
(b) Explain your drawing in (a) above
(c) Name the machine used in the experiment above
(d) What would happen if the seedling was put horizontally outside the machine
(e) Name the stimuli investigated and type(s) of response expected in the experiment
Date posted: October 7, 2019. Answers (1)
- The diagram below illustrate enzyme controlled reaction.(Solved)
The diagram below illustrate enzyme controlled reaction.
a) State the relationship between rate of reaction and enzyme concentration
b) Account for the rate of reactions between;
i) Q and R
ii) R and S
iii) U and V
c) Name one other factor that affects enzyme action, not illustrated above
Date posted: October 7, 2019. Answers (1)
- The relationship between seed fresh mass in the lupin lupinus and percentage seed germination, percentage seedling survival and seedling fresh mass is shown in the...(Solved)
The relationship between seed fresh mass in the lupin lupinus and percentage seed germination, percentage seedling survival and seedling fresh mass is shown in the table.
a) How was percentage germination in column two of the table calculated?
b) Why was seed fresh mass preferred to seed dry mass to take measurements of the seed weight in the experiment
c)
i) Explain why the measurements of mean seedling fresh mass (5) weeks after germinated may not have been an accurate measurement of growth that had occurred.
ii) How could more meaningful and accurate measurement been obtained in c(i) above?
d) With reference to the figures in the taste indicate the relationship between seed fresh mass and percentage seed germination, percentage seedling survival and seedling fresh mass.
e) Suggest an explanation why seedling produced from large seeds grow more rapidly than the
seedling produced from small seeds
Date posted: October 7, 2019. Answers (1)
- Name the type of cell division that produces gametes.(Solved)
Name the type of cell division that produces gametes.
Date posted: October 7, 2019. Answers (1)
- The diagram below represents a set-up that was used to investigate the effect of rotation on the growth of a bean radicle. The set-up allowed...(Solved)
The diagram below represents a set-up that was used to investigate the effect of rotation on the growth of a bean radicle. The set-up allowed the seedling to rotate slowly and continuously for seven days.
(a) Name the piece of apparatus illustrated.
(b)
(i) State the observation made on the shape of the radicle after seven days
(ii) Explain the observation in (b) (i) above
(c) Suggest a suitable control for this experiment.
(d) Give any four importance of tropism in plants.
Date posted: October 7, 2019. Answers (1)
- The following data represents the development in dry mass of germinating seedlings within 18 weeks:(Solved)
The following data represents the development in dry mass of germinating seedlings within 18 weeks:
(a) Write reference to the graph, explain the changes in dry mass between:-
(i) Week 0 to 2
(ii) Week 5 to 13
(iii) Week 16 - 18
(b)
(i) What is the significance of time zero?
(ii) What difference would be expected from the above results if the experiment started with the seeds? Give a reason for your answer
(c)
(i) Describe how you carry out the experiment to obtain dry mass in the respective weeks
(ii) State one advantage of using dry mass instead of fresh weight in estimating growth of an organism
Date posted: October 7, 2019. Answers (1)
- The experiment set – up below was designed to investigate an aspect of germination.(Solved)
The experiment set – up below was designed to investigate an aspect of germination.
a) Why was potassium hydroxide pellets used in this experiment?
b) What was the role of moist cotton wool in this experiment?
c) i) By means of an arrow, indicate on the diagram the direction in which red dye would move
during the experiment.
ii) Give reason for your answer in c(i) above.
d) Other than the factor investigated above, state any other one factor necessary for germination
process.
Date posted: October 7, 2019. Answers (1)
- The diagram below represents a stage during the process of germination.(Solved)
The diagram below represents a stage during the process of germination.
(a) (i) Name the type of germination illustrated in the diagram
(ii) Give a reason for your answer in (a) (i) above.
(b) Give two functions of the part labelled X
Date posted: October 7, 2019. Answers (1)
- Define the following terms:
a) Growth
b) Development(Solved)
Define the following terms:
a) Growth
b) Development
Date posted: October 7, 2019. Answers (1)
- The diagram below represents a growth pattern of arthropods.(Solved)
The diagram below represents a growth pattern of arthropods.
(a) Name the type of growth pattern represented on the graph.
(b)Identify the process represented by X.
(c) Which hormone is responsible for process at X in (b) above?
Date posted: October 7, 2019. Answers (1)
- The illustration below represents an eye defect.(Solved)
The illustration below represents an eye defect.
Date posted: October 7, 2019. Answers (1)
- An experiment was carried out to investigate the rate of growth of pollen tube against time.
The results are shown in the table below.(Solved)
An experiment was carried out to investigate the rate of growth of pollen tube against time.
The results are shown in the table below.
(b) (i) At what intervals was the growth of the pollen tube measured?
(ii) What was the length of pollen tube at; 130 minutes
(iii) At what time was the length of the pollen tube 18mm?
(iv) With reasons, describe the growth pattern of the pollen tube between:
- 0 to 120minutes
- Reason
- 120 to 180 minutes
- Reason
v) State the importance of the growth of pollen tube to the plant
(c) State the changes that take place in a flower after fertilization
Date posted: October 7, 2019. Answers (1)