Breakdown of Абонентская плата зависит от тарифной ставки.
Questions & Answers about Абонентская плата зависит от тарифной ставки.
Because it is the subject of the sentence — the thing that depends on something.
- абонентская плата = the subscription fee / monthly fee
- зависит = depends
In Russian, the subject normally appears in the nominative case, so:
- абонентская — nominative feminine singular
- плата — nominative feminine singular
The adjective agrees with the noun in gender, number, and case.
The verb зависеть simply takes the pattern от + genitive in Russian.
So:
- зависеть от чего? = to depend on what?
This is just the normal government pattern of the verb, and it has to be memorized as part of the verb:
- зависеть от погоды = to depend on the weather
- зависеть от цены = to depend on the price
- зависеть от обстоятельств = to depend on circumstances
So in your sentence, от is there because зависеть requires it.