The insecticide kills most of the insects when introduced; those that survive; give rise to a new
generation of flies that are resistant to insecticide.
Kavungya answered the question on June 15, 2019 at 08:14
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Explain why certain drugs become ineffective in curing a disease after many years of use
(Solved)
Explain why certain drugs become ineffective in curing a disease after many years of use
Date posted:
June 15, 2019
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Answers (1)
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All insects are believed to have arisen from a common ancestor. However, modern insects differ widely in a variety of ways such as in the...
(Solved)
All insects are believed to have arisen from a common ancestor. However, modern insects differ widely in a variety of ways such as in the adaptation of their mouthparts for different modes of feeding. What kind of evolution is this?
Date posted:
June 15, 2019
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Answers (1)
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Give two factors that determine water reabsorption in the distal convoluted tubule
(Solved)
Give two factors that determine water reabsorption in the distal convoluted tubule
Date posted:
June 15, 2019
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Answers (1)
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Distinguish between the struggle for existence and survival for the fittest as used in the theory of natural selection
(Solved)
Distinguish between the struggle for existence and survival for the fittest as used in the theory of natural selection
Date posted:
June 15, 2019
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Answers (1)
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Describe how a population of grasshoppers in a given area can be estimated
(Solved)
Describe how a population of grasshoppers in a given area can be estimated
Date posted:
June 15, 2019
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Answers (1)
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Explain how food as a factor regulates the population of animals in an ecosystem
(Solved)
Explain how food as a factor regulates the population of animals in an ecosystem
Date posted:
June 15, 2019
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Answers (1)
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Apart from mere observation of actual feeding suggest two methods that can be used to determine the type of food eaten by animals
(Solved)
Apart from mere observation of actual feeding suggest two methods that can be used to determine the type of food eaten by animals
Date posted:
June 15, 2019
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Answers (1)
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A fish farmer wanted to know the number of fish in a pond. He collected 10 fish from the pond
and labeled each, by a tag...
(Solved)
A fish farmer wanted to know the number of fish in a pond. He collected 10 fish from the pond
and labeled each, by a tag label on its fin and returned the ten fish to the pond to mix with
other fish . When he later collected 50 fish from the pond, he found only four of them had labels
a) Estimate the total number of fish in the pond (show your workings)
b) What two assumptions are being made in this methods of estimating population
Date posted:
June 15, 2019
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Answers (1)
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An investigation was carried out on a terrestrial ecosystem. The population sizes and species biomass were determined and recorded as shown in the table...
(Solved)
An investigation was carried out on a terrestrial ecosystem. The population sizes and species
biomass were determined and recorded as shown in the table
a) If these organisms had a feeding relationship, construct a simple food chain involving all the organisms
b) Construct pyramid of numbers using the data provided above
c) State one disadvantage of using pyramid of number in expressing feeding relationships in ecological ecosystem
Date posted:
June 15, 2019
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Answers (1)
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In a certain school Form three class did an experiment to estimate the number of Tilapia
in their fish pond. 725 tilapia were netted marked and...
(Solved)
In a certain school Form three class did an experiment to estimate the number of Tilapia
in their fish pond. 725 tilapia were netted marked and released.
a) State the method used in this exercise
b) Calculate the tilapia population.
c) State two assumptions made by the students during the investigation
Date posted:
June 15, 2019
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Answers (1)
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Use the food web below to answer the questions that follow:-
(a) Construct a food chain ending with crocodile as a quartenary consumer
(b) Name the organisms...
(Solved)
Use the food web below to answer the questions that follow:-
(a) Construct a food chain ending with crocodile as a quartenary consumer
(b) Name the organisms in the food web hat has only one predator
Date posted:
June 15, 2019
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Answers (1)
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Explain why Biomass of producers is greater than that of primary consumers in a balanced ecosystem.
(Solved)
Explain why Biomass of producers is greater than that of primary consumers in a balanced ecosystem.
Date posted:
June 15, 2019
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Answers (1)
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Explain why the biomass of organisms decreases at each preceding trophic level.
(Solved)
Explain why the biomass of organisms decreases at each preceding trophic level.
Date posted:
June 15, 2019
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Answers (1)
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Birds feed on grasshoppers that feed on grass.
Draw a possible food chain from the above information
(Solved)
Birds feed on grasshoppers that feed on grass.
Draw a possible food chain from the above information
Date posted:
June 15, 2019
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Answers (1)
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A student wanted to estimate the number of grasshoppers in 5km2 grass field near the school compound.
Using a sweep net he captured 36 grasshoppers. He...
(Solved)
A student wanted to estimate the number of grasshoppers in 5km2 grass field near the school compound.
Using a sweep net he captured 36 grasshoppers. He used a red felt pen to mark the thorax of each insect before releasing back into the field. Three days later he made another catch of grasshoppers. He collected 45 grasshoppers of which only 4 had been marked with red mark.
a) Name the above method used in the population estimation
b) Calculate the population of grasshoppers using the above data
Date posted:
June 15, 2019
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Answers (1)
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The graph below shows the changes in transpiration rate and the width of the stomatal aperture in Zea mays (maize) over a 24-hour period.
a) What...
(Solved)
The graph below shows the changes in transpiration rate and the width of the stomatal aperture in Zea mays (maize) over a 24-hour period.
a) What is meant by the term transpiration?
b) Account for the rate of transpiration between
i)3am and 5am
ii)6am -12 noon
iii)1.00 pm -9.00 pm
Date posted:
June 14, 2019
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Answers (1)
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Suggest the biological significance of each of the following
i) Development of the pollen tube in fertilization in plants.
ii) Fusion of petals to form funnel-shaped corolla...
(Solved)
Suggest the biological significance of each of the following
i) Development of the pollen tube in fertilization in plants.
ii) Fusion of petals to form funnel-shaped corolla tube in certain
flowers.
Date posted:
June 14, 2019
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Answers (1)
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The diagram below shows exchange of materials between embryo’s bloodstreams and mother’s blood stream(i) Give the names of the parts labelled E and GEG(ii) Name...
(Solved)
The diagram below shows exchange of materials between embryo’s bloodstreams and mother’s blood stream
(i) Give the names of the parts labelled E and G
E
G
(ii) Name one substance that is in high concentration in E
(iii) In which organ does this kind of exchange shown occur?
Date posted:
June 14, 2019
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Answers (1)
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In a physiological experiment, starch, protein, diastase and sodium chloride (common salt) were added
to water and put inside a visking tubing. The visking tubing was...
(Solved)
In a physiological experiment, starch, protein, diastase and sodium chloride (common salt) were added
to water and put inside a visking tubing. The visking tubing was then placed in a water bath maintained at a temperature between 350C and 400C. The set-up was as shown in the diagram below.
The following observations were made after the procedures indicated.
(a) Name the process by which salt moved into the water in the beaker from the visking tubing.
(b) (i) Name the food substance responsible for the brown colour observed after one hour both in the beaker and visking tubing when solutions were boiled with Benedict’s solution.
(ii) Account for the observation in b(i) above.
(c) (i) Name the food substance tested with sodium hydroxide followed by copper sulphate solutions.
(ii) Account for the absence of the food substance named in c(i) above in the beaker after1 hour.
(d) After one hour, the visking tubing was firm. State the term used to describe this state.
Date posted:
May 29, 2019
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Answers (1)
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The figure below shows a germinating seedling.
(a) Name the parts labelled. A,B C
(b) Give three important environmental conditions that are necessary for seed germination...
(Solved)
The figure below shows a germinating seedling.
(a) Name the parts labelled. A,B C
(b) Give three important environmental conditions that are necessary for seed germination and state why they are important.
(c) The part labelled D was removed from the above seedling three months later. After a few days the plant became bushy with several lateral branches.
(i) What is this phenomenon called?
(ii) Why did the removal of the stem tip result in a shorter plant with bushy growth?
Date posted:
May 29, 2019
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Answers (1)