STD 11 - 3. Plant kingdom — NEET STD 11 Science — Question

Which of the following statements are correct ?
(i) Vernalisation refers to the promotion of flowering by a period of high temperature.
(ii) The spring variety of crops are normally planted in the spring and come to flower before the end of the growing season.
(iii) It is not seen in biennial plants.
(iv) Subjecting cold treatment to sugar beet will result in flowering.
(v) Cytokinins specially help in delaying senescence.
(vi) Auxins are involved in regulating apical dominance.
(vii) Ethylene is specially useful in enhancing seed germination.
(viii) Gibberellins are responsible for immature falling of leaves.
(ix) Cytokinins promote senescence.
(x) Auxins control apical dominance.
(xi) Gibberellins promote shoot elongation.
(xii) Abscissic acid enables seeds to withstand desiccation.
Choose the correct option given below :-

The main plant body of Selaginella sp. is

Growth rings are formed due to activity of

In Pinus megaspore on germination forms

Which of the following statements are true for nucleic acid ?
(i) For nucleic acids, the building block is a nucleotide.
(ii) Heterocyclic compounds in nucleic acids are adenine, guanine, uracil, cytosine and thymine.
(iii) Adenine and guanine are substituted purines while the rest are substituted pyrimidines.
(iv) The sugar found in polynucleotides is either ribose or deoxyribose.
(v) Ribose or deoxyribose is a erythrose sugar which is found in nucleotides.
(vi) A nucleic acid containing deoxyribose is called deoxyribonucleic acid (DNA) while that which contains ribose is called ribonucleic acid (RNA).

Male gemetes are flagellated in

Restriction enzymes are isolated chiefly from: