Cataracts Facts. 1  Cataracts are changes in clarity of the natural lens inside the eye that gradually degrade visual quality. The natural lens sits behind the colored part of the eye (iris) in the area of the pupil, and cannot be directly seen with the naked eye unless it becomes extremely cloudy.
Hershey and Chase. Alfred Hershey and Martha Chase did an Experiment in 1952 that was called the Hershey-Chase Experiment. This experiment set out to determine what composed the genetic material of a bacteriophage. A bacteriophage is a virus that infects a bacterium.
A quasi-experiment is an empirical study used to estimate the causal impact of an intervention on its target population without random assignment. Quasi-experimental research shares similarities with the traditional experimental design or randomized controlled trial, but it specifically lacks the element of random assignment to treatment or control.