does this sentence make sense?
Because rivers are becoming extremely polluted, many plants and animals are dying.
Yes, it makes perfect sense.
A better way to phrase this would be to say, "Many plants and animals are dying because rivers are becoming extremely polluted."
Yes, the sentence "Because rivers are becoming extremely polluted, many plants and animals are dying" does make sense. It conveys a cause-and-effect relationship between the pollution of rivers and the negative impact on plants and animals.
To determine if a sentence makes sense, you can analyze its structure and meaning. In this case, the sentence has a logical structure and the subject and predicate are clearly connected. The cause ("Because rivers are becoming extremely polluted") is stated first, followed by the effect ("many plants and animals are dying"). The sentence conveys a clear meaning that pollution in rivers is leading to the death of plants and animals.