A psychiatrist is studying the effects of healthy eating habits on mood improvement. He identifies 25 people who eat healthy food and 25 who do not. Each of the 50 people is given a questionnaire designed to determine their mood. None of the 50 people who participated in the study knew they were part of a study. Which statement is true? (NOT A) This is a double-blind study.

This is an experiment in which eating habits is a blocking variable.

This is an observational study.

This is a randomized comparative experiment.

This is a matched-pairs design.

With these 5 geometry questions! pls 1.)quadrilateral abcd is inscribed in this circle.what is the measure of ∠a ? enter your answer in the box.°2.)quadrilateral abcd is inscribed in a circle.what is the measure of angle a? enter your answer in the box.m∠a= 3.)quadrilateral abcd is inscribed in this circle.what is the measure of angle b? enter your answer in the box.m∠b= °4.)quadrilateral abcd is inscribed in this circle.what is the measure of angle a? enter your answer in the box.°5.) quadrilateral abcd is inscribed in this circle.what is the measure of angle c? enter your answer in the box.°