Environmental factors early in life can have long-lasting effects on an organism.

In one study, researchers examined whether dietary supplementation with vitamins C and E influences body mass and corticosterone level in yellow-legged gull chicks. Chicks were randomly assigned to either the non supplemented group or the vitamin supplement experimental group. The initial study group consisted of 108 nests, with 3 eggs per nest. Chicks were assessed at age 7 days.

(a) What type of study is this?

(b) What are the experimental and control treatments in this study?

(c) Explain why randomization is an important feature of this experiment.