What is the required temperature for the induction of callus from an explant?

Tissue culture technique requires

The pH of the nutrient medium in plant tissue culture is adjusted between:

Read the following statements:
$I.$ Colostrum is recommended for newborns because it is rich in antigens.
$II.$ Chikungunya is caused by a Gram-negative bacterium.
$III.$ Tissue culture has proved useful in obtaining virus-free plants.
$IV.$ Beer is manufactured by the distillation of fermented grapes.
How many of the statement$(s)$ is/are correct?

Select the correct sequence for the production of somatic hybrid plants in somatic hybridization.
$I -$ Isolation of protoplasts
$II -$ Digestion of cell wall
$III -$ Regeneration of somatic hybrid plants
$IV -$ Isolation of cells
$V -$ Fusion of protoplasts of two different varieties
$VI -$ Formation of hybrid protoplasts

Identify the incorrect statements from the following:
$(i)$ Callus is obtained in $2$ to $3$ weeks.
$(ii)$ Suspension culture does not show faster growth compared to callus culture.
$(iii)$ Orchid seeds do not contain stored food.
$(iv)$ $2,4-D$ is used only in callus culture.