Scientistshaveobtainedmoreevidence___________plasticisfindingitswayintothehumanbody.

Mr. Smith gradually _____ a knowledge of the subject.

Scientists have obtained more evidence ___________ plastic is finding its way into the human body.

Between the two parts of the concert is an interval, __________ the audience can buy ice-cream.

Recently a survey _______ prices of the same goods in two different supermarkets has caused heated debate among citizens.