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(a) Counter - current flow (system) ;
(b) This ensure efficient diffusion of oxygen from water into blood i.e there is continuous diffusion of oxygen from water
into blood ;
Eventually blood that leaves the gills has almost the same concentration of oxygen as the water that enter the gills /
maintains a steep diffusion gradient between water and blood ;
sharon kalunda answered the question on May 24, 2019 at 09:25
- State three sites of gaseous exchange in mesophytes.(Solved)
State three sites of gaseous exchange in mesophytes.
Date posted: May 24, 2019. Answers (1)
- The diagram below shows an experiment on germination peas.
a) (i) What changes are observable at the end of the experiment?
(ii) Give the reason the...(Solved)
The diagram below shows an experiment on germination peas.
a) (i) What changes are observable at the end of the experiment?
(ii) Give the reason the observation in a(i) above.
(b) If water had been used instead of caustic potash in the experiments, what would be observed?
Date posted: May 24, 2019. Answers (1)
- State one use for each of the following apparatus in the study of living organisms.
(a) Hand lens.
(b) Pair of forceps.(Solved)
State one use for each of the following apparatus in the study of living organisms.
(a) Hand lens.
(b) Pair of forceps.
Date posted: May 24, 2019. Answers (1)
- Why does food stored in a refrigerator remain unspoiled longer than it does under ordinary conditions?(Solved)
Why does food stored in a refrigerator remain unspoiled longer than it does under ordinary conditions?
Date posted: May 24, 2019. Answers (1)
- Explain how various human activities cause soil pollution.(Solved)
Explain how various human activities cause soil pollution.
Date posted: May 24, 2019. Answers (1)
- Describe the way by which terrestrial plants are adapted to living in arid and semi-arid ecosystems.(Solved)
Describe the way by which terrestrial plants are adapted to living in arid and semi-arid ecosystems.
Date posted: May 24, 2019. Answers (1)
- Describe the adaptations of wind pollinated flowers.(Solved)
Describe the adaptations of wind pollinated flowers.
Date posted: May 24, 2019. Answers (1)
- The diagram below represents one of the joints in the mammalian skeleton.
a) Name the type of joint shown in the diagram.
b) Name the parts labelled...(Solved)
The diagram below represents one of the joints in the mammalian skeleton.
a) Name the type of joint shown in the diagram.
b) Name the parts labelled Z and U
c) Name two parts at the body where this type of joint is found.
d) State the functions of the fluid found in W.
e) Name the structure which attaches muscles to the bones at a joint.
Date posted: May 24, 2019. Answers (1)
- The diagram below represent a seedling.
a) Name the structure labelled B
b) State the functions of the parts labelled A and C
c) Name the...(Solved)
The diagram below represent a seedling.
a) Name the structure labelled B
b) State the functions of the parts labelled A and C
c) Name the type of germination exhibited by the seedling.
d) State three conditions within the seed necessary for germination.
e) What is the importance of optimum temperature in seed germination ?
Date posted: May 24, 2019. Answers (1)
- The diagram below represents a transverse section of a young stem.
a) Name the parts labelled A and C on the diagram.
b) State the functions...(Solved)
The diagram below represents a transverse section of a young stem.
a) Name the parts labelled A and C on the diagram.
b) State the functions of the parts labelled B, D and E
c) List three differences between the section shown above and one that would be obtained from the
root of the same plant.
Date posted: May 24, 2019. Answers (1)
- State the function of goblet cells.(Solved)
State the function of goblet cells.
Date posted: May 24, 2019. Answers (1)
- The diagram below is a cross section through a part of human ileum.
a) i) Identify the structure drawn above.
ii) State the significance of the...(Solved)
The diagram below is a cross section through a part of human ileum.
a) i) Identify the structure drawn above.
ii) State the significance of the structure shown above.
b) Name the parts labelled A, B and C
c) Give the functions of the part labelled B and C.
Date posted: May 24, 2019. Answers (1)
- Give two reasons why Drosophila melanogaster (Fruit fly) are considered suitable organisms for
use in genetic experiments.(Solved)
Give two reasons why Drosophila melanogaster (Fruit fly) are considered suitable organisms for
use in genetic experiments.
Date posted: May 24, 2019. Answers (1)
- Where does glycolysis take place in a cell ?(Solved)
Where does glycolysis take place in a cell ?
Date posted: May 24, 2019. Answers (1)
- At what stage do chromatids separate during meiosis ?(Solved)
At what stage do chromatids separate during meiosis ?
Date posted: May 24, 2019. Answers (1)
- Akol observed and drew an amoeba using a light microscope. If the total magnification of the amoeba was X450 and that of the objective lens...(Solved)
Akol observed and drew an amoeba using a light microscope. If the total magnification of the amoeba was X450 and that of the objective lens was X30. What was the magnification of the eyepiece lens ? Show your working.
Date posted: May 24, 2019. Answers (1)
- Describe an experiment to investigate the effects of unilateral source of light on growth of seedlings.(Solved)
Describe an experiment to investigate the effects of unilateral source of light on growth of seedlings.
Date posted: May 24, 2019. Answers (1)
- In an experiment, 900 viable seeds of a certain plant species were divided into groups of 100 seeds each. Each group of
seeds was placed at...(Solved)
In an experiment, 900 viable seeds of a certain plant species were divided into groups of 100 seeds each. Each group of
seeds was placed at different temperatures but same conditions of air and moisture. The percent germination was
determined after 10 days. The table below shows percent germination at the various temperatures.
a) Using a suitable scale, draw a graph of percent germination against temperature.
b) Account for percent germination at :
i) 50°
ii) 30°C
iii) 40°C
c) Explain the role played by each of the following factors in the germination of seeds.
i) Water.
ii) Air.
Date posted: May 24, 2019. Answers (1)
- State TWO features of the endodermis.(Solved)
State TWO features of the endodermis.
Date posted: May 24, 2019. Answers (1)
- The diagram below represents phloem tissue from the stem of a plant.
i) Name the structure labelled A.
ii) State TWO substances transported in the phloem....(Solved)
The diagram below represents phloem tissue from the stem of a plant.
i) Name the structure labelled A.
ii) State TWO substances transported in the phloem.
iii) Give the function of cell B.
Date posted: May 24, 2019. Answers (1)