Biology
Assertion (A): Collenchyma is composed of long and narrow cells. These cells have very thick walls due to the deposition of lignin.
Reason (R): Collenchyma stores food and provides temporary support to the parts of a plant.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Tissues
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Answer
A is false and R is True.
Reason — Collenchyma cells are long and narrow, but their thickening is due to cellulose and pectin, not lignin. Lignin is found in sclerenchyma, not collenchyma.
Collenchyma store food and provides mechanical support, to growing parts like young stems and leaves.
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Related Questions
Deepali tried to match the kind of supporting tissues in plants with their characteristic features.
She tabulated the pairs as follows:Supporting tissue Cellular structure P Dead cells, have thick walls due to deposition of lignin Q Elongated cells, cell wall is thickened at the corners Identify P and Q
- P — Collenchyma, Q — Sclerenchyma
- P — Sclerenchyma, Q — Collenchyma
- P — Parenchyma, Q — Sclerenchyma
- P — Collenchyma, Q — Parenchyma
Assertion (A): Lateral (or cambium) meristem is responsible for the increase in the girth (diameter) of the stem.
Reason (R): Cambium is located near the tips of the root and stem and also on the tips of axillary buds where growth occurs at a faster rate.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Assertion (A): Tracheids are made up of elongated dead cells with large cavities without any contents.
Reason (R) : Tracheids help in the conduction of prepared food from the leaves to other parts of a plant.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Assertion (A): Lymph is a fluid connective tissue which does not contain any blood cells.
Reason (R): Lymph is concerned with transportation and immunity.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.