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caledon eNotes educator| Certified Educator

49a. Corn can germinate in soil with salt concentrations ranging from 0mg/L to 400mg/L, but a salt concentration of 800mg/L is normally lethal and will result in no germinations. To test the ability of a new strain of corn to germinate in salty conditions, it will be planted in soils with a variety of salt concentrations. It is hypothesized that the percentage of successful germinations will be inversely proportional to the salt concentration of the soil, with germinations approaching zero near the lethality concentration.
49b. The hypothesis was supported; the corn showed a decline in germination as salt concentrations approached the lethality mark (800mg/L). Note that the scientist did not hypothesize that the new strain would succeed in salty soil, because she had no evidence that it would before she began the experiment.

50. Plants are important because;

  1. They are largely responsible for the current state of the Earth's atmospheric composition and the dominance of motile aerobic life.
  2. They are the base of virtually every food chain/web and comprise the bulk of living organic material.
  3. They are the primary source of fossil fuels.
  4. They are valuable indicators of ecological health and lack the more complicated behavioral patterns of animals, making them more useful in certain situations for environmental research.

51a. The data shows that grasses were the least affected during all points of the study, but particularly in the aftermath of the logging, when they showed little difference in diversity from the 45-year mark. The data shows that shrubs recovered relatively quickly, but trees took considerably longer. It also shows that increasing diversity is complimentary to multiple species; as trees become more diverse, so too do shrubs and grass. We should note that there is a slight "hiccup" in the data at the 15-year mark, with a overall decrease in diversity; however it is not clear from the data provided if this is a part of an ecological imbalance and competition, or the side effect of another factor such as a drought or fire.

51b. The data patterns indicate that the environment is recovering from the logging process.

52. Using plants for biofuel will significantly reduce the environmental effects of drilling for fossil fuels, and will probably reduce the economic instability stemming from these fuels being located in few, and diminishing, sources around the world. It will drastically reduce issues of fuel transportation, as fuels can be made on-site anywhere in the world. However, it raises the questions of where this biomass will come from, and whether its use as biofuel will reduce the biomass available for usage elsewhere. Additionally, as the world population increases, there will be an increase in demand for fuels; biofuel may not be capable of meeting this demand without impacting food supplies, such as in the use of corn to produce ethanol.

adarshanurag | Student

Answer for IMAGE 3.............

45. The  following 3 factors that lead to a massive decline in pollinators population:-

      i. pesticides and fungicides ii. pathogens iii. parasites. 

46. Vegetative reproduction is the process by which plant is able to reproduce through its special vegetative parts like

      leaves, bulb, Rhizome, stem, root, etc.

      Advantages of vegetative reproduction:-

      i. New plants need not always grow from seeds and thus, many more plants can be produced commercially than

         would occur naturally.

      ii. New plants having the same desired characteristics of mother plant can be obtained.

     iii. Desired features of more than one plant can be introduced into a single plant through grafting.

47. a. Advantages: It gives the gene  which are multitude of features and the genes have a larger chance of survival if a

         disease hits. Disadvantages: Cross pollination is slower when compared to self pollination and The natural process

         of pollination becomes delayed in this case.

      b. Advantages of self pollination include less chance of failure of pollination and maintaining purity of race.

          Disadvantages of self pollination include new species are not produced. Another disadvantage is that

          weaker progeny happens with continuous self pollination.