Possessive adjective or just "it"? [duplicate]

Solution 1:

The survival of a TV channel depends [on it /its attracting as many viewers as possible].

There’s no difference in the meaning or the grammar, though using the genitive pronoun "its" is seen as being slightly more formal - that’s all.

The bracketed element is a preposition phrase headed by "on"; the PP functions as complement of the verb “depends”. Functioning as complement to the preposition “on” is the gerund-participial clause, which has "it /its" as subject, "attracting" as verb, and the comparative expression "as many viewers as possible" as object. Note that the two as’s are in construction as part of the comparison.

Regarding the contrast between "it" and "its" as subject: older grammars would analyse "attracting" as a gerund when used with genitive "its". Modern grammars do not usually use the term ‘gerund’ like this; "attracting" would simply be analysed as a verb as can be seen from the way it takes an object "as many viewers as possible", as I outlined above.