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.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Answer
A is false and R is True.
Reason — A is false as collenchyma cells are long and narrow, but their thickening is due to cellulose and pectin, not lignin. Lignin is found in sclerenchyma, not collenchyma.
R is True as collenchyma store food and provides mechanical support, to growing parts like young stems and leaves.
Therefore, A is false and R is True is the correct option.
Related Questions
Sandesh observed a slide containing the longitudinal section of a plant tissue found in all parts of the plant like-root, stem and leaves. Different types of cells are visible in the tissue as shown alongside in the diagram:
(a) Identify and name the kind of tissue shown above. Is it a kind of simple permanent tissue or complex tissue ?
(b) Distinguish between simple permanent tissue and complex permanent tissue.
(c) Write one important role of the above mentioned tissue.
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.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): Tracheids are made up of elongated dead cells with large cavities without any contents.
Reason (R) : Tracheids provide mechanical support by developing various types of thickenings in their walls.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): Lymph is a fluid connective tissue which does not contain any blood cells.
Reason (R): Lymph is concerned with transportation and immunity.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.