CBSE Class 10 Sample Paper Science Solution - For 2023 Boards

(a) Why is it not possible to reconstruct the whole organism from a fragment in complex multicellular organisms?

(b) Sexual maturation of reproductive tissues and organs are necessary link for reproduction. Elucidate.

 

Answer:

(a)

  • Many multi-cellular organisms are not simply a random collection of cells.
  • Specialised cells are organised as tissues , and tissues are organised into organs , organised into organ systems , which then are placed at definite positions in the body. 
  • Therefore, cell-by-cell division (which is asexual) to form different types of cells with different structures and functions would be impractical

CELLS ARE THE BASIC STRUCTURAL AND FUNCTIONAL UNIT OF LIFE - Teachoo.jpg

(b) 

Sexual maturation of reproductive tissues is a necessary link for reproduction.

  • This is because of the need for germ-cells to participate in sexual reproduction
  • The germ-cells are produced only in mature reproductive tissues .
  • The body of the individual organism has to grow to its adult size .
  • When the rate of general body growth begins to slow down , reproductive tissues begin to mature. 

The maturation of these tissues leads to changes in the appearance of the body like change in body proportions and appearance of new features

  • This period during adolescence is called puberty
  • There are also changes taking place that are different between boys and girls
  • In girls, breast size begins to increase , with darkening of the skin of the nipples.
  • Girls also begin to menstruate during puberty. 
  • Boys begin to have new thick hair growth on the face and pubic regions and their voices begin to crack .

PUBERTY IN GIRLS - Teachoo.jpg

PUBERTY IN BOYS - Teachoo.jpg

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CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo