Thursday 25 August 2011

CBSE Class IX ( 9th) Science | Chapter 8. Motion | Lesson Exercises

Questions with in the  Chapter 

Page 100 (CBSE Class IX ( 9th) Science Textbook - Chapter 8. Motion )
Question 1. An object has moved through a distance. Can it have zero displacement? If yes, support your answer with an example.
Answer : Yes, an  object even after it has moved through a distance, it can have zero displacement. As we know distance is just length of the path an object has covered irrespective of its direction or position with reference to certain point, where as the shortest distance measured from the initial to the final position of an object is known as the displacement.

Monday 8 August 2011

CBSE Class IX ( 9th) Science | Chapter 7. Diversity in Living Organisms | Lesson Exercises

Question 1. What are the advantages of classifying organisms?

Answer : There are many advantages of classifying organisms which are given as below
1. Classifying organisms helps us in recognising the basic arrangement of a hierarchical structure among diverse species.
2. It tells us about the resemblances and relationships between various organisms thus facilitating studies or research of wide variety associated with organisms effortlessly.
3. It helps in understanding the evolution of organisms, as it gives us most of the information permitting a reconstruction of phylogeny of life.

Saturday 6 August 2011

CBSE Class IX ( 9th) Science | Chapter 6. Tissues | Lesson Exercises

Question 1. Define the term tissue.
Answer : Tissue may be defined as a group or cluster of cells that are similar in structure and work together to achieve a particular function.Tissue as a cluster of cells performs a particular function at a definite place in the body.With in a tissue, cells are arranged or designed to give the highest possible efficiency of function. Blood, phloem and muscle are all examples of tissues.

Question 2. How many types of elements together make up the xylem tissue?
Name them.

Wednesday 3 August 2011

CBSE Class IX ( 9th) Science | Chapter 5. THE FUNDAMENTAL UNIT OF LIFE | Lesson Exercises

Question 1. Make a comparison and write down ways in which plant cells are different from animal cells.
Answer :
Comparison Between Plant Cells & Animal cells
Plant CellsAnimal Cells
  1. Plant cells have one, large central vacuole occupying almost 90% of cell volume.
  2. Plant cells have Plastids.
  3. Plant cells have Cell wall and a cell membrane.
  4. In plant cells, Lysosomes usually not evident.
  5. Plant cells generally do not have Cilia.
  6. Plant cells have round (irregular)
  7. Plant cells have chloroplasts because they make their own food
  1. Animal cells have one or more small vacuoles (much smaller than plant cells).
  2. Animal cells do not have Plastids
  3. Animal cells have a cell membrane only
  4. In Animal cells, Lysosomes occur in cytoplasm.
  5. Animal cells have Cilia
  6. Animal cells have rectangular (fixed shape)
  7. Animal cells don't have chloroplasts