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Science 9

Science 9 · Worksheets

Mixed review · Living things and their environment

Ten questions of mixed difficulty, covering Biological diversity, Environmental chemistry. Print it, or work through it on screen — the answer key starts on its own page.

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Mixed review · Living things and their environment

Science 9 · maddyhelps.com

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Circle the best answer for each question. Show your work in the space provided.

  1. In pea plants, purple flower colour (P) is dominant over white (p). A plant that inherited one P and one p has

    1. a) white flowers
    2. b) pale purple flowers, a blend of both
    3. c) purple flowers
    4. d) some purple and some white flowers

  2. Two golden retriever puppies from the same litter have slightly different coat colours. This is an example of

    1. a) variation between species
    2. b) a change caused by the environment
    3. c) two different species mixing
    4. d) variation within a species

  3. A bacterium copies its DNA and splits into two identical cells. This type of reproduction is

    1. a) budding
    2. b) spore formation
    3. c) sexual reproduction
    4. d) binary fission

  4. The three numbers on a bag of fertilizer, such as 10-20-10, stand for the amounts of

    1. a) carbon, hydrogen and oxygen, in that order
    2. b) nitrogen, potassium and phosphorus, in that order
    3. c) nitrogen, phosphorus and potassium, in that order
    4. d) calcium, phosphorus and sodium, in that order

  5. A farmer cuts one high-yielding potato into pieces and plants each piece. The main advantage of this asexual method is that

    1. a) every new plant has the same genes as the high-yielding parent
    2. b) the new plants will vary more, so some of them may resist disease
    3. c) the cut pieces mutate into plants that yield even more
    4. d) each new plant gets genes from two different parents

  6. A species' niche is

    1. a) its role in the ecosystem: what it eats, what eats it, how it lives
    2. b) the physical place where it lives, such as a pond, marsh or forest
    3. c) the number of its members living in one area at one time
    4. d) the other species it competes against for food and space

  7. Some organisms reproduce asexually while conditions are good, then switch to sexual reproduction when conditions get worse. The best explanation is that sexual reproduction

    1. a) produces offspring identical to both parents, so they are protected
    2. b) produces many more offspring, in less time, than asexual reproduction does
    3. c) produces varied offspring, so some are likely to suit the new conditions
    4. d) needs no partner, so it is easier when food and space run short

  8. Bacteria are used to clean up a fuel spill in soil. They will break down the fuel fastest where the soil is

    1. a) warm, moist and well supplied with oxygen
    2. b) waterlogged, with very little oxygen in it
    3. c) dry, so the fuel stays in a single place
    4. d) frozen, so the fuel cannot spread further

  9. A plantation grows only one banana variety, and every plant is a clone. A new fungus arrives that this variety cannot resist. The biggest danger is that

    1. a) the whole crop could be lost, since no plant has genes to resist it
    2. b) the bananas will quickly breed resistance among themselves
    3. c) only the oldest plants will die, since the young ones are stronger
    4. d) the fungus will cause mutations that make the plants resistant

  10. A student blows through a straw into water containing bromothymol blue. The blue solution turns green and then yellow. This shows that the breath

    1. a) made the water neutral, because oxygen from the breath dissolved
    2. b) had no chemical effect; the warm air changed the indicator's colour
    3. c) made the water acidic, because carbon dioxide forms an acid in water
    4. d) made the water basic, because carbon dioxide forms a base when it dissolves

Answer key · Mixed review · Living things and their environment

Science 9 · maddyhelps.com

  1. c) purple flowers — A dominant trait shows whenever at least one copy is present, so Pp looks purple. The white trait is still carried and can appear in the next generation, but traits do not blend, which is the mistake behind the pale purple answer.
  2. d) variation within a species — Members of one species share the same basic features but differ in the details, and that is variation within a species. Variation between species is the bigger kind of difference, such as a dog compared with a cat.
  3. d) binary fission — Binary fission means splitting in two, and both new cells are identical to the parent. Budding is different: a small outgrowth forms on the parent, as in yeast, and breaks off later.
  4. c) nitrogen, phosphorus and potassium, in that order — N-P-K: nitrogen, phosphorus and potassium are the three macronutrients plants need in the largest amounts. The order never changes, so a bag reading 10-20-10 is highest in phosphorus.
  5. a) every new plant has the same genes as the high-yielding parent — Asexual reproduction makes clones, so a good variety stays exactly as it is. More variation is the advantage of sexual reproduction, and the price of cloning is that one disease can strike every plant equally.
  6. a) its role in the ecosystem: what it eats, what eats it, how it lives — A niche is a species' whole way of life: its food, its predators, and when and where it is active. The physical place is its habitat, and mixing up niche and habitat is the usual mistake.
  7. c) produces varied offspring, so some are likely to suit the new conditions — Mixing genes from two parents gives variety, and in a changing environment variety raises the odds that some offspring survive. Asexual reproduction is usually the faster way to multiply, which is exactly why it is used while conditions are good.
  8. a) warm, moist and well supplied with oxygen — Biodegradation is done by living microorganisms, and they work fastest where conditions suit living things: warmth, moisture and oxygen. Freezing may stop the fuel spreading, but it nearly stops the bacteria too.
  9. a) the whole crop could be lost, since no plant has genes to resist it — Clones share identical genes, so a disease that kills one can kill them all. Variation is a population's insurance, which is why seed banks store many varieties of each crop and not just today's best one.
  10. c) made the water acidic, because carbon dioxide forms an acid in water — Bromothymol blue is blue in a base, green near neutral and yellow in an acid. Carbon dioxide from breath dissolves to form a weak acid, carbonic acid, and that is what turns the indicator yellow.