Question

please answer questions 4 and 8
50 points please answer fast​

Answer 1

Answer:

Explanation:

4th Answer:

Parenchyma - 1) it has a primary cell wall 

                    2) cell walls are thin 

                    3) cell wall is made up of cellulose

Collenchyma-1) it also  has a primary cell wall

                    2) cell walls are thick at corners 

                    3) cell wall is made up of cellulose

Sclerenchyma-1) it has a secondary cell wall  

                     2) cell wall is very thick reducing the cellular space of the                                 cell 

                     3) cell wall is made up of "lignin" 

8th answer:

♣ STRAITED MUSCLE FIBRES :

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→ They are long cylindrical cells.

→ The fibres have blunt ends.

→ They possess striations or alternate light and dark bands.

→ Intercalated discs and cross connections are absent.

→ The muscle fibre is multi nucleate . nuclei are oval in outline . They occur peripherally below the sarcolemna.

→ They occur in bundles.

→ Straited muscle fibres occur in limbs, hands, feet , body wall, tongue , pharynx and upper part of oesophagus.

→ They are voluntary .

→ They are able to perform fast and powerful contractions.

→ They soon get fatigued.

♣ SMOOTH MUSCLE FIBRES :

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→ The fibres are elongated and spindle shaped.

→ The fibres have pointed ends.

→ Striations or light and dark bands are absent.

→ Intercalated discs and cross- connections are absent.

→ Smooth Muscle Fibres is uninucleate . nucleus is centrally placed , oval or elongated.

→ They generally form sheets.

→ The fibres occur in dermis, urinogenitical tracts, digestive tract , lungs, Iris, blood vessels, etc.

→ They are involuntary.

→ They perform slow but prolonged contractions.

→ Fatigue is rare.

♣ CARDIAC MUSCLE FIBRES :

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→ The cells are small and cyclindrical.

→ The fibres have broad ends. Striations are present but they are fainter than those of Straited muscle fibres.

→ Intercalated discs and cross- connections are present.

→ The cells are uninucleate . nucleus in oval- rounded . It is centrally placed.

→ They form a network.

→ The muscle fibres occur only in the wall of heart.

→ They are involuntary.

→ cardiac Muscle fibres performs powerful and rhythmic contractions.

→ They seldom get fatigued.

hope it helps.

Answer 2

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Paranchyma:-

1) it has a primary cell wall.

2) cell walls are thin.

3) cell wall is made up of cellulose.

Collenchyma:-

1) it also has a primary cell wall

2) cell walls are thick at corners

3) cell wall is made up of cellulose