IMAT 2020 Q39 [Healthy Living Organisms]

Which of the following statements about healthy living organisms are correct?

  1. They are made up of one or more cells.
  2. They have DNA as the genetic material.
  3. They use energy to stay alive when their surroundings change.
  4. They undergo phases of growth.

A. 1, 2 and 4 only
B. 1, 2, 3 and 4
C. 1, 2 and 3 only
D. 2, 3 and 4 only
E. 1, 3 and 4 only

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The correct answer is B.

First things first, organisms come in all shapes and forms. They are made of cells, and can either be unicellular or multicellular.

  • Unicellular organisms are either procaryotes or eukaryotes. The difference between prokaryotes and eukaryotes is the fact that their DNA is not surrounded by a nuclear membrane. In other words, the have no nuclei : instead, they have a structure called the nucleoid.

    Speaking of DNA, the genetic code is considered “universal” because all of the bases (A, T, C, G) code for the same amino-acids among all species.

  • Multicellular organisms are all species of plants and animals, some fungi and algae. To achieve that kind of structure, they undergo processes of cell division or aggregation of cells.

Moreover, there are a few criteria that help define whether or not “something” is alive. The main ones are :

  1. Reproduction : it produces offspring
  2. Nutrition and energy processing
  3. Growth and development

Based on these elements, we can say that all of the 4 items are correct, and thus, B is the right answer.

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