More Dogs Are Being Diagnosed with Thyroid Problems Than Have

Multiple Choice

More dogs are being diagnosed with thyroid problems than have been diagnosed in the past. A
Researcher identified 50 puppies without thyroid problems and kept records of their diets for
Several years to see if any developed thyroid problems. This is a(n)

A) survey
B) retrospective study
C) prospective study
D) blocked experiment
E) randomized experiment