Question

1. They are the professors in our university.

2. They are all the profesors in our university.
[#1 mean #2, does't it?]

3. They are professors in our university.
4. They are some of the professors in our university.
[#3 mean #4, does't it?]

5. They study the sea animals in Antarctica.
6. They study all the sea animals in Antarctica.
[#5 mean #6, does't it?]

7. They study sea animals in Antarctica.
8. They study some of the sea animals in Antarctica.
[Does #7 mean #8?]

Answer 1

All those pairs’ correctness or error depends on the context in which they are written. They all seem correct to me, but it really depends on context.