Which type of study design is used in the following scenario:
a researcher interested in the incidence of chlamydia enrolls 1,000 college seniors. sexual habits are identified at baseline and every 6 months thereafter for four years. new cases of chlamydia are recorded over the four year follow-up period.

Plz ! cattle ranchers and dairy farmers rarely allow all of their animals to reproduce instead they practice selective breeding and only encourage the reproduction of animals with specific features. which of the following cows would a dairy farm most likely choose to reproduce? a. a cow that makes a lot of milk. b. a cow that can run quickly. c. a cow with a think, soft fur. d. a cow with large, strong hooves.