State two ways in which schistosoma species is adapted to parasitic mode of life. (Answered)
Name a method that could be used to estimate the population size of the following organisms:
(i) Fish in a pond.
(ii) Black jack in a garden. (Answered)
Give three reasons for loss of energy from one trophic level to another in the food chain. (Answered)
Distinguish between pyramid of numbers and pyramid of biomass.
(Answered)
What is the importance of the following in an ecosystem?
(a) Decomposers
(b) Predation. (Answered)
Name the organism that causes amoebic dysentery. (Answered)
Explain how abiotic factors affect plants. (Answered)
How is aerenchyma tissue adapted to its function? (Answered)
What is meant by Synecology? (Answered)
(a) What is meant by Autecology? (Answered)
Name the causative agent of typhoid. (Answered)
How are leaves of submerged plants adapted for photosynthesis? (Answered)
Ascaris lumbricoides is an example for an endoparasite.
(a) The name Ascaris refers to?
(b) State the habitat of the organism.
(c) State three ways in which the organism is adapted to living in its habitat. (Answered)
Explain why the carrying capacity of wild beasts is higher than that for cattle in a given piece of land. (Answered)
(b) State the association of the bacteria named in (a) above with the leguminous plants. (Answered)
The diagram below represents the nitrogen cycle.
(a) State the process labeled: A and D
(b) Name the compound represented by B.
(c) Name the group of organisms labeled C.
(d) (i) Name the group of plants which promote process A.
(ii) State the part of the plant where process A takes place.
(e) How would excess pesticides in the soil interfere with process A? (Answered)
Why are green plants referred to as primary producers in an ecosystem? (Answered)
Explain how leaves of mesophytes are suited to their functions. (Answered)
What is the importance of a national park to a nation? (Answered)
State four human activities that affect population of animals in game parks. (Answered)
Explain how birds of prey are adapted to obtaining their food. (Answered)
State two ways in which some fungi are beneficial to humans. (Answered)
Give a reason why two species in ecosystems cannot occupy the same niche. (Answered)
Explain how the various activities of man have caused pollution of air. (Answered)
(a) Distinguish between a community and population. (Answered)
Suggest three reasons why green plants are included in a fish aquarium. (Answered)
The herbivorous mammalian species were introduced into an ecosystem at the same time and in equal numbers. The graph below represents their populations during the first seven years.
Study the graph and answer the questions that follow.
(a) (i) Which species has a better competitive ability?
(ii) Give reason for your answer.
(b) Account for the shape of the curve of species A between:
(i) One year (Answered)
State two ways by which the human immuno deficiency virus (H.I.V) is transmitted through sexual intercourse? (Answered)
Give two reasons why primary productivity in an aquatic ecosystem decreases with depth. (Answered)
What is the relationship between leguminous plants and bacteria found in their root nodules? (Answered)
Describe how the tapeworm is adapted to a parasitic mode of life. (Answered)
The diagram below represents a simplified nitrogen cycle.
(a) Name the organisms that cause process E and J
(b) Name the process represented by F and H.
(c) Name the group of organism represented by G. (Answered)
The diagram below represents a feeding relationship in an ecosystem.
(a) Write down the food chains in which the guinea fowls are secondary consumers.
(b) What would be the short term effects on the ecosystem if lions invaded the area?
(c) Name the organism through which energy from the sun enters the food wed. (Answered)
Oil can be applied on the stagnant water to control the spread of malaria.
(a) How does this practice control the spread of malaria.
(b) Give a reason why this practice should be discouraged. (Answered)
Describe how the quadrant method can be used to estimate the population of various species of plants in a given habitat. (Answered)
The chart below shows a feeding relationship in a certain ecosystem.
(a) Construct two food chains ending with a tertiary consumer in each case.
(b) Which organism has the largest variety of predators in the food web?
(c) Name secondary consumers in the food web. (Answered)
Figure 6 shows an athlete lifting weights while standing with the feet apart.
Explain why standing with the feet apart improves the athlete’s stability. (Answered)
State the principle of moments. (Answered)
Giving a reason, name the state of equilibrium of the toy. (Answered)
Figure 3 shows a bimetallic strip with a wooden handle, suspended horizontally
using a thin thread.
The strip is heated at the point shown. Explain why the system tips to the right. (Answered)
Figure 3 shows a rectangular block of wood with a hollow section (inside) at the
position shown. The block is resting on a horizontal bench
(i) State the effect on the stability of the block when the hollow section is filled with water.
(ii) Explain your answer in (i) above. (Answered)
Figure 3 shows two identical trolleys with loads A and B.the loads are identical in
shape and size. Given that the density of A is greater than that of B,
explain why the trolley in figure 3(ii) is more stable. (Answered)
If the portion of the rock represented by the shaded part is chopped off, explain
why the rock may topple to the right. (Answered)
Figure 3 shows two identical hollow spheres. Sphere A is completely filled with the
liquid while B is partially filled with identical liquid. When the two spheres are
rolled gently on a horizontal surface, it is observed that the sphere B stops earlier
than the sphere A. Explain this observation. (Answered)
Figure 2 shows a beaker placed on a bench. A block of ice is placed in the beaker
as shown.
State and explain the change in the stability of the beaker when the ice melts. (Answered)
State how the position of the centre of gravity of a body in stable equilibrium
changes to that in the rest position when the body is slightly tilted and then
released. (Answered)
State two factors that should be controlled in manufacturing a cylindrical
container of uniform thickness, which should normally be in a standing position. (Answered)
What is meant by the centre of gravity of a body? (Answered)
Figure 3 shows two metal rods A and B of equal length made of same material but different diameters. Wax is attached at one end of each rod. A source of heat is placed between the two metal rods.
State with reason, what is observed on the wax. (Answered)