Scientists in a particular field strive for the same quality of work because they know their peers will be reviewing their scientific claims. what does this review process ensure?

The review process mentioned is called peer review and it is when the scientists work and research is put to the scrutiny of other experts in the same field of research to check its validity (making sure it's claims are correct or justified) and evaluate whether is is a suitable piece of work for publication.  So it's for validity of the work and whether it can be published.

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.