Companion cell in plants are associated with

• vessels

• sieve elements

• sperms

• guard cells

Mossess and ferns are found in moist and shady places because both

• require presence of water for fertilization

• do not need sunlight for photosynthesis

• depend for their nutrition on microorganisms which can survive only at low temperature

• cannot compete with sun-loving plants.

13.

Cork cambium results in the formation of cork which becomes impermeable to water due to the accumulation of

• resins

• lignins

• suberin

• tannins.

Assertion: Diabetes insipidus is marked by excessive urination and too much thirst of water.

Reason: Anti-diuretic hormone (ADH) is secreted by the posterior lobe of pituitary gland,

• If both Assertion and Reason are true and Reason is the correct explanation of Assertion

• If both Assertion and Reason are true but Reason is not the correct explanation of Assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false.

Assertion: Ginger has a prostrate-growing rhizome.

Reason: Shoot growth is not effected by gravity

• If both Assertion and Reason are true and Reason is the correct explanation of Assertion

• If both Assertion and Reason are true but Reason is not the correct explanation of Assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false.

Assertion: Photomodulation of flowering is a phytochrome - regulated process.

Reason: Active form of phytochrome (Pfr) directly induces floral induction in shoot buds.

• If both Assertion and Reason are true and Reason is the correct explanation of Assertion

• If both Assertion and Reason are true but Reason is not the correct explanation of Assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false.

Assertion: The epithelial layer of scutellum of maize is both secretory and absorptive in function.

Reason: The epithelial layer secretes hormones into the endosperm for the synthesis of food
solubilising enzymes and also absorbs and transfers the solubiliscd food to embryo axis.

• If both Assertion and Reason are true and Reason is the correct explanation of Assertion

• If both Assertion and Reason are true but Reason is not the correct explanation of Assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false.

Assertion: Nitrogen-fixing bacteria in legume root nodules survive in oxygen-depleted cells of nodules.

Reason: Legheamoglobin completely removes oxygen from the nodule cells.

• If both Assertion and Reason are true and Reason is the correct explanation of Assertion

• If both Assertion and Reason are true but Reason is not the correct explanation of Assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false.

Assertion: Deficiency of sulphur causes chlorosis in plants.

Reason: Sulphur is a constituent of chlorophyll, proteins and nucleic acids.

• If both Assertion and Reason are true and Reason is the correct explanation of Assertion

• If both Assertion and Reason are true but Reason is not the correct explanation of Assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false.

Cultivation of Bt cotton has been much in the news. The prefix Bt means

• "Barium-treated" cotton seeds

• "Bigger thread" variety of cotton with better tensile strength

• produced by "biotechnology" using restriction enzymes and ligases 

• carrying an endotoxin gene from Bacillus thuringienesis.