Perfect Tense with and without agent

Question

Is it necessary to have agent while constructing Perfect tense?. I mean some activities are spontaneous like Fallen, grow up, increased, expired etc.

Tree has been fallen. Water level has been increased. My account has been expired.

Some more examples

Villages around the area have been cut off from the outside world, Visave said. Nearly 50 villages in the district have been cut-off from the tehsil headquarters and two bridges remained submerged as heavy rain continued to lash Thane on Wednesday.

Answer 1

Yes, it is grammatically fine to have a perfect tense in the passive voice (i.e. no expressed agent).

My father has been injured.

Your example sentences, however, don't work, each for separate reasons.

*Tree has been fallen.

We can't use "fall" as a transitive verb, i.e. "I fall the tree" is not an English sentence. You can't make an intransitive verb passive. There is an old-fashioned transitive verb, "to fell," which you could use (but most people would say "cut down." Also, you need an article on the tree.

The tree had been cut down.

Your next sentence,

*Water level has been increased.

is basically right, this one's just missing a "the," which is a separate issue.

The water level has been increased.

Your third sentence has a similar problem to the first sentence.

*My account has been expired.

Again, "expire" is typically an intransitive verb, so it doesn't work in the passive. You could say "the bank has closed my account," and so you could say

My account has been closed.