Pollen grains of a plant whose $2n = 28$ are cultured to get callus by tissue culture method. What would be the number of chromosomes in the cells of the callus?

Given below are two statements:
Statement $I$: In suspension culture and callus culture technique,subculturing is necessary.
Statement $II$: Subculturing is needed only in suspension culture technique.
In the light of above statements,select the correct option given below:

Arrange the following steps of somatic hybridisation in a correct sequence.
$A$. Digestion of cell walls.
$B$. Isolation of naked protoplasts.
$C$. Fusion of protoplasts to get hybrid protoplast.
$D$. Isolation of single cells from two different varieties of plants.
$E$. Growing of hybrid protoplast to form a new plant.
Choose the correct answer from the options given below:

Which of the following is $NOT$ an objective of embryo culture?

Assertion : In plant tissue culture,somatic embryos can be induced from any plant cell.
Reason : Any viable plant cell can differentiate into somatic embryos.

The culture medium (nutrient medium) can be referred to as a 'highly enriched laboratory soil'. Justify the statement.