NCERT Class-9 Science Solutions: Chapter 7-Diversity in Living Organisms Part 10 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Long Answer Questions

Question 50:

Write names of few thallophytes. Draw a labelled diagram of Spirogyra.


The Thallophytes (Thallophytes or Thallobionta) are a group of non-mobile organisms that are traditionally described as “thalloid plants” or “lower plants” .

These plants mainly grow in water. They include fungus, lichens and algae and occasionally bryophytes, bacteria and the Myxomycota of Plantae kingdom.

A few examples of Thallophytes are -

Ulothrix, Spirogyra, Cladophara, Ulva and Chara

Image the Spirogyra

Question 51:

Thallophyta, Bryophyta and Pteridophyta are called as ‘Cryptogams’ . Gymnosperms and Angiosperms are called as ‘phanerogams’ . Discuss why? Draw one example of Gymnosperm.


The Thallophyta, Bryophyta and Pteridophyta are called as ‘Cryptogams’ because the reproductive organs of these groups are inconspicuous or hidden. Seeds are absent. On the other hand ‘Phanerogams’ include gymnosperms and angiosperms which have well differentiated reproductive tissue and the embryo with stored food. Embryo develops into seed.

Image the Pinus and Cycas

Question 52:

Define the terms and give one example of each

  1. Bilateral symmetry
  2. Coelom
  3. Triploblastic


  1. The left and right halves of the body have the same design, eg, liver fluke
  2. Coelom is the internal body cavity between visceral organs and body wall in which well-developed organs can be accommodated, eg. butterfly
  3. Animals having three layers of cells from which differentiated tissue can be made are called triploblastic, eg. star fish
Image the Butterfly and Asterias

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