Question 35 (Choice 1) - CBSE Class 10 Sample Paper Science Solution - For 2023 Boards - Solutions to CBSE Sample Paper - Science Class 10

(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 . 

(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 .