Sample 1Medium
A figure shows a longitudinal view of a root tip with four regions, from the tip upwards: A is a thimble-like covering at the very tip; B is a region of small, dividing cells a few millimetres above A; C is a region of cells that are rapidly lengthening; D is a region where cells differentiate, and some epidermal cells there bear fine thread-like outgrowths. In which region do root hairs arise?
- A
A, the root cap
- B
B, the region of meristematic activity
- C
D, the region of maturation
- D
C, the region of elongation
Show the answer
The answer is C.Behind the root cap come the region of meristematic activity, the region of elongation and then the region of maturation. Some epidermal cells of the region of maturation form root hairs, which absorb water and minerals.
- A.
A is the root cap, which protects the tender apex as it moves through the soil. It does not form root hairs.
- B.
B is the region of meristematic activity. Its cells are small, thin-walled and dividing, and they do not form root hairs.
- D.
C is the region of elongation, where cells enlarge rapidly and so lengthen the root. Root hairs appear only after the cells mature.
NCERT: Class 11 Biology, Chapter 5
Sample 2NEET level
Match List I with List II. List I A. Rhizophora B. Banyan tree C. Opuntia D. Pea List II I. Prop roots that hang from branches and support them II. Leaflets modified into tendrils III. Roots that grow vertically upwards to get oxygen for respiration IV. Stem modified into a flattened green structure that photosynthesises Choose the correct answer from the options given below.
- A
A-I, B-III, C-IV, D-II
- B
A-III, B-I, C-II, D-IV
- C
A-IV, B-I, C-III, D-II
- D
A-III, B-I, C-IV, D-II
Show the answer
The answer is D.Rhizophora, growing in swamps, has pneumatophores that grow upwards to get oxygen, and the banyan has prop roots. Opuntia has a flattened green stem, and in pea the leaflets are modified into tendrils.
- A.
Swaps pneumatophores and prop roots between Rhizophora and banyan.
- B.
Gives tendrils to Opuntia and the flattened stem to pea.
- C.
Gives Rhizophora the flattened stem and Opuntia the pneumatophores.
NCERT: Class 11 Biology, Chapter 5 (Morphology of Flowering Plants), The Root and The Stem (modifications)