31. Which of the
following is true for nucleolus?
(1) It takes part in spindle formation
(2) It is a membrane-bound structure
(3) Larger nucleoli are present in dividing cells
(4) It is a site for active ribosomal RNA synthesis
(1) It takes part in spindle formation
(2) It is a membrane-bound structure
(3) Larger nucleoli are present in dividing cells
(4) It is a site for active ribosomal RNA synthesis
Answer (4) It is a site for active ribosomal RNA synthesis
32. Stomatal movement is not affected by(1) O2 concentration
(2) Light
(3) Temperature
(4) CO2 concentration
Answer(1) O2 concentration
33. The stage during which separation of the paired homologous chromosomes begins is(1) Diakinesis (2) Diplotene (3) Pachytene (4) Zygotene
Answer (2) Diplotene
34. Stomata in grass leaf are
(1) Rectangular
(2) Kidney shaped
(3) Dumb-bell shaped
(4) Barrel shaped
Answer (3) Dumb-bell shaped
35. Secondary xylem and phloem in dicot stem are produced by(1) Phellogen
(2) Vascular cambium
(3) Apical meristems
(4) Axillary meristems
Answer (2) Vascular cambium
36. Pneumatophores occur in(1) Carnivorous plants
(2) Free-floating hydrophytes
(3) Halophytes
(4) Submerged hydrophytes
Answer (3) Halophytes
37. Casparian strips occur in
(1) Cortex (2) Pericycle (3) Epidermis (4) Endodermis
Answer (4) Endodermis
38. Plants having little or no secondary growth are(1) Conifers
(2) Deciduous angiosperms
(3) Grasses
(4) Cycads
Answer (3) Grasses
39. Sweet potato is a modified(1) Tap root
(2) Adventitious root
(3) Stem
(4) Rhizome
Answer (2) Adventitious root
40. Which of the following statements is correct?(1) Horsetails are gymnosperms
(2) Selaginella is heterosporous, while Salvinia is homosporous
(3) Ovules are not enclosed by ovary wall in gymnosperms
(4) Stems are usually unbranched in both Cycas and Cedrus
Answer (3) Ovules are not enclosed by ovary wall in gymnosperms