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i) Temperature- changes in temperature affect the rate of biochemical reactions (enzymatic or metabolic) for example
photosynthesis
ii) Light (intensity, duration and wavelength)
-Plants (green) need light energy for photosynthesis
-plants need light for flowering
-some seeds like lettuce need light for germination
iii) Wind
-influences the rate of transpiration
-disperses fruits, seeds and spores for reproduction
-is an agent of pollination
iv) Humidity
-influences the rate of transpiration in plants
v) pH
-plants require specific pH to grow well (ie acidic, alkaline or neutral)
vi) Salinity
-influences the distribution of some plant species in the ecosystem eg Only those with salt tolerant tissues grow in saline areas eg Mangroves
vii) Topography
-influences the growth of plants ie plants in the leeward side have stunted growth while plants on the windward side have normal growth.
viii) Rainfall (water)
-affects the distribution of plant species in different areas.
-water is needed for seed germination; absorption of minerals;] as a raw material for photosynthesis; and as a solvent for mineral salts
-influences turgidity to bring about support in plants
-water is needed for dispersal of some seeds and fruits.
ix) Pressure (Atmospheric pressure
- influences carbon IV oxide availability which affects photosynthesis.
- affects the rate of transpiration
- influences the amount of O2/O2 concentration hence affecting respiration.
x) Mineral slats
- plants thrive best where there are enough mineral salts and in their correct proportions.
- affect the distribution of other plant species ie insectivorous plants grow in soils deficient in nitrates hence device other methods of acquiring the nutrient.
sharon kalunda answered the question on May 27, 2019 at 10:06
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Describe the role of the mammalian liver in carbohydrate metabolism.
Date posted: May 27, 2019. Answers (1)
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In an experiment, lactic acid concentration was measured before, during and after exercise to determine the effect of exercise on the concentration of lactic acid in blood. Study the data obtained and use it to answer the questions that follow.
a) Plot a graph of the concentration of lactic acid against time using a suitable scale. (6 marks)
b) From the graph:
i) Determine the period of exercise.
ii) Explain
c) i) Determine the time when oxygen debt incurred.
ii) Explain
d) i) The duration it took to pay back the oxygen debt
ii) Explain
e) Plot a hypothetical curve for oxygen intake during the experimental period on the same axes.
f) Why does lactic acid level usually continue to rise in the blood after the exercise ceases?
g) State two of effects of lactic acid on tissues.
Date posted: May 27, 2019. Answers (1)
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Name the gland associated with the secretion of aldosterone hormone.
Date posted: May 27, 2019. Answers (1)
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a) Name the organ.
b) Identify the parts R and S.
c) i) State three...(Solved)
The diagram below is a longitudinal section of an organ in mammals.
a) Name the organ.
b) Identify the parts R and S.
c) i) State three differences in the structure above found in the desert rat and fish.
ii) Account for the differences stated above.
(d) Name the gland associated with the secretion of aldosterone hormone.
Date posted: May 27, 2019. Answers (1)
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a) i) Which part of the alimentary canal is represented by the portion...(Solved)
The diagram below is a cross section of a portion of alimentary canal.
a) i) Which part of the alimentary canal is represented by the portion above.
ii) Give a reason for your answer in (a) (i) above.
b) i) State two functions of the part of alimentary canal represented above.
ii) Explain two structural adaptations of the part of alimentary canal represented above.
Date posted: May 27, 2019. Answers (1)
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The colour of tips of hair in Shepherd dog is controlled by a gene with three alleles B for Black, R for red and C for copper.
A cross between pure breeding red and copper hair tips produce offsprings with scarlet hair tips. Crossing pure breeding
red and black hair tips yields all red offsprings. A cross between pure breeds of copper and black produce offsprings that
are all copper.
a) Comment on the inheritance of the three alleles B, R and C.
b) A dog breeder wishes to know the genotype of a dog with red hair tips. State and explain the cross needed to determine
the dog’s genotype.
c) A mother of blood group AB was married to a man of blood group B heterozygous. What is the probability that one of
their sons would be blood group A? Show your working.
Date posted: May 27, 2019. Answers (1)
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Give three types of movable joints found in mammalian skeleton.
Date posted: May 27, 2019. Answers (1)
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Distinguish between exocrine and endocrine glands.
Date posted: May 27, 2019. Answers (1)
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Using a diagram show how the defect can be corrected.(Solved)
The diagram below shows an eye defect.
Using a diagram show how the defect can be corrected.
Date posted: May 27, 2019. Answers (1)
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What is the significance of the high tail power in fish locomotion.
Date posted: May 27, 2019. Answers (1)
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The length from tail tip to the anus in a fish is 8cm whereas that from tail tip is 24cm. Calculate the tail power of the fish.
Date posted: May 27, 2019. Answers (1)
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a) Name the nucleic acid.
b) Give a reason for your answer in (a) above.
c) Write down the complimentary base...(Solved)
Below is a nucleic strand.
a) Name the nucleic acid.
b) Give a reason for your answer in (a) above.
c) Write down the complimentary base pairing the pattern in the nucleic acid formed above.
Date posted: May 27, 2019. Answers (1)
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and N.
State the...(Solved)
The diagram below represents a young root and four cells which occur in different regions of the root tip labelled K, L, M
and N.
State the regions of the root tip where each of the cells A B C D occur.
Date posted: May 27, 2019. Answers (1)
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List two possible effects that are likely to occur if the maternal and foetal circulatory system were directly connected.
Date posted: May 27, 2019. Answers (1)
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a) Identify the stage.
b) Give a reason for your answer in (a) above....(Solved)
The diagram below shows a cell undergoing a stage in a cell division.
a) Identify the stage.
b) Give a reason for your answer in (a) above.
Date posted: May 27, 2019. Answers (1)
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a) Construct a pyramid representing representing the order of feeding in the grassland.
b) Describe two features...(Solved)
The following organisms were found in a grassland habitat.
a) Construct a pyramid representing representing the order of feeding in the grassland.
b) Describe two features expected along trophic levels of pyramid constructed.
Date posted: May 27, 2019. Answers (1)
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a) Identify two mistakes in the name above.
b) Write the correct name of cockroach.(Solved)
A student named cockroach as AMERICAN PERIPLANTA.
a) Identify two mistakes in the name above.
b) Write the correct name of cockroach.
Date posted: May 27, 2019. Answers (1)
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i) Name the kingdom to which the organism belong.
ii) Give a reason for your answer in a (i) above.(Solved)
The diagram below represents an organism.
i) Name the kingdom to which the organism belong.
ii) Give a reason for your answer in a (i) above.
Date posted: May 27, 2019. Answers (1)
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Explain why;
i) There are no plasma proteins in the urine.
ii) Urea...(Solved)
The table below shows percentage composition of blood plasma and urine from different substances.
Explain why;
i) There are no plasma proteins in the urine.
ii) Urea concentration is greater in the urine than in the blood plasma.
iii) There is glucose in the urine
Date posted: May 27, 2019. Answers (1)
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a) Birds
b) Shark
c) Cow(Solved)
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a) Birds
b) Shark
c) Cow
Date posted: May 27, 2019. Answers (1)