(a) Describe six protective adaptations used by animals against predation and give one example in each case.
(b)(i) What is pollution?
(ii) State six human activities which cause pollution.
(a) Explain briefly the following terms:
(i) phenotype
(ii) hybrid
(iii) dominant character.
(b) Two varieties of maize, one with yellow (Y) grains and the other with purple (y) grains were crossed and all their offspring had yellow grains. When the offspring were crossed with the parent variety with purple grains, half of the resulting offspring had yellow grains, while the other half had purple grains. Using labelled diagrams only;
(i) deduce the genotype of the grains of the first filial generation,
(ii) show the results of the cross between the first filial generation and the parent purple variety.
(c) Mention two ways in which the application of genetics is beneficial to agriculture.
(a) Describe an experiment to show that green plants require sunlight for photosynthesis. (Details of test for starch not required)
(b) What other conditions are necessary for photosynthesis?
(c) Name the part of a dicotyledonous leaf where most food is manufactured, giving reasons.
(d) What happens to the manufactured food?
(a) Distinguish between pollination and fertilization in plants.
(b)(i) State five features which ensure cross pollination in plants.
(ii) Name one plant example for each feature
(c)(i) Name three agents of pollination
(ii) State three features of wind-dispersed fruits/seeds.
(a)(i) What is a joint?
(ii) List three types of movable joints and mention one location in the mammalian body of each type.
(b)(i) Make a labelled diagram, 8-10cm long, of a typical movable joint.
(iii) Explain how the structure of the joint adapts it to its function.
(a) What is a habitat?
(b) Describe the energy flow in a freshwater habitat.
(c) List (i) three biotic factors; (ii) five abiotic factors which affect plants in freshwater habitat.
The theory of evolution by natural selection was first put forward by
- A. Aristotle
- B. Darwin
- C. Linnaeus
- D. Boyle
Which of the following is not included in the theory of natural selection?
- A. struggle for existence
- B. offspring show variation
- C. inheritance of adaptive structures
- D. disappearance of functionless organs
Which of the following organisms exhibit division of labour?
- A. houseflies
- B. butterflies
- C. cockroaches
- D. termites
Which of the following statements is correct about the chromosomes in the gametes? At the end of the second
meiotic division
- A. each gamete contains only paternal hereditary information
- B. chromosomes contain a random mixture of paternal and maternal chromosomes.
- C. chromosomes in the four gamete cells are diploid in number
- D. chromosomes contain only maternal hereditary information
In the F1 generation of Mendel’s experiment obtained by crossing pea plants of long stems with those of short stems,
What was his observation?
- A. some were short while others were long
- B. all were long
- C. half of them were long while half were short
- D. three-quarters were long while one quarter were short,
Heterozygous tall plants were crossed with pure-breeding dwarf plants of the same species. What were the approximate percentages of the offspring?
- A. 100% tall 0% dwarf
- B. 75% tall 25% dwarf
- C. 50% tall 50% dwarf
- D. 25% tall 75% dwarf
Which of the following traits in humans can be affected by environmental factors?
- A. skin colour
- B. eye colour
- C. baldness
- D. tongue-rolling
What will be the genotypic ratio when two heterozygous red pea plants are crossed?
- A. 1 : 0
- B. 1 : 2 : 1
- C. 2 : 1
- D. 3 : 1
In man, sex is determined by the inheritance of
- A. a pair of homologous chromosomes
- B. an extra chromosome in the cells of a female
- C. a dominant gene for maleness present in man
- D. two similar X chromosomes in the female and X and Y chromosomes in the male.
The ability of some individuals to taste phenylthiocarbamide (PTC) is a
- A. morphological adaptation
- B. morphological variation
- C. physiological adaptation
- D. physiological variation
Which of these physiological variations is sex-linked?
- A. albinism
- B. blood groups
- C. sickle-cell anaemia
- D. haemophilic condition
Tropical rain forests can be conserved by the following practices except?
- A. agroforestry
- B. deforestation
- C. shifting cultivation
- D. crop rotation
Which of the following practices does not contribute to intensive depletion of forest resources in West Africa?
- A. Use of powerful tools for felling trees
- B. regrowing of forest trees
- C. clearance of forests for cash crops
- D. use of fire or hunting in forests
The following are natural resources except
- A. rubber
- B. soil
- C. water
- D. cellophane
An abandoned refuse dump mag’ be a good site for an intending vegetable farmer because
- A. . very little manual work would be done by the farmer
- B. microbial activity had released nutrients into the soil
- C. the roots of vegetable seedlings easily get enough light
- D. refuse dumps possess plenty of gas which scares away rodents