Question

Please answer this questions..

Class 9th..​

Answer 1

Answer:

4 ) perenchyma

• cell wall is thin
• made up of cellulose

collenchyma

• cell wall is thick
• made up of cellulose and pectin

sclerenchyma

• cell wall hard, rigid , very thick
• made up of lignin - a waterproof meterial

5 ) If water enters the guard cells , they swell up and the stoma pore opens

If water leaves the guard cells, they become flaccid and the stoma pore closes

6 ) Smooth muscle

• Has spindle - shaped nonstraited uninucleated fibers
• occurs in walls of internal organs
• is involuntary

Cardiac muscle

• Has striated , branched , uninucleated fibers .
• occurs in walls of heart
• is involuntary

Skeletal muscle

• Has striated tubular, multinucleated fibers
• Is usually attached to skeleton
• is voluntary

7 ) Myocardium has three types of muscle fibres

• Muscle fibres which form contractile unit of heart ( 99 % )
• Muscle fibres which form pacemaker
• Muscle fibres which form conductive system

8 ) Striated muscle

• They are cylindrical in shape and multi nucleate
• They are present in body parts such as hands and legs

Unstriated muscle

• They spindle shaped and uninucleated
• They are present in the wall of food canal , stomach, mouth , iris etc

cardiac muscle

• They are cylindrical branched and uninucleated
• They are present the heart