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Compare the three main types of life cycles in multicellular organisms as described below. Determine which comparison is accurate and which also gives an appropriate example of an organism that employs each type.

a) Haploid-dominant: Mosses; Diploid-dominant: Fungi; Alternation of generations: Humans
b) Haploid-dominant: Ferns; Diploid-dominant: Animals; Alternation of generations: Plants
c) Haploid-dominant: Algae; Diploid-dominant: Bryophytes; Alternation of generations: Ferns
d) Haploid-dominant: Animals; Diploid-dominant: Flowering plants; Alternation of generations: Fungi

1 Answer

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Final answer:

The correct comparison of life cycles is haploid-dominant in fungi, diploid-dominant in animals, and alternation of generations in plants. Fungi have a mainly haploid life cycle; animals, a diploid life cycle; and plants exhibit both haploid and diploid multicellular stages.

Step-by-step explanation:

To compare the three main types of life cycles in multicellular organisms, let us review each one and provide appropriate examples:

  • Haploid-dominant life cycles, mostly found in fungi and some algae, involve organisms spending the majority of their life cycle in a haploid state. The multicellular organism is made up of haploid cells that reproduce through mitosis. During sexual reproduction, haploid cells from two parents form a diploid zygote, which quickly undergoes meiosis to create new haploid cells.
  • Diploid-dominant life cycles, common in animals and flowering plants, have a multicellular organism that exists mostly in the diploid state. Gametes are the only haploid cells, and after fertilization, the resulting zygote grows into a diploid multicellular organism.
  • The Alternation of generations type, which is a blend of the haploid and diploid extremes, is seen in plants like ferns. Both haploid and diploid stages are multicellular; the haploid stage (gametophyte) produces gametes, and the diploid stage (sporophyte) produces spores through meiosis that grow into gametophytes.

Therefore, based on the provided descriptions, the correct comparison is (b): Haploid-dominant life cycle is exemplified by fungi, Diploid-dominant life cycle by animals, and Alternation of generations life cycle by plants.

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