A study showed that people who take vitamin C daily have a significantly better chance of protecting against a cold than those who did not take the vitamin daily. Which of the following statements is correct?

I. This is an observational study and not an experiment.

II. This study provides evidence that taking vitamin C daily contributes to protecting against a cold.

III. The general health consciousness of people who take vitamin C could be a confounding variable.

a. I only

b. III only

c. I and III only

d. II and III only

e. I, II, and III

The rate of decay of a radioactive substance depends upon the amount present initially. the mass y (mg) of the radioactive substance cobalt-60 present in a sample at time t (years) is represented by the exponential equation y=50e −0.1315 t . answer the following questions in complete sentences. 1. how does the exponential equation above compare to the equation for simple interest that is compounded continuously? explain the similarities. 2. what is the initial amount of cobalt-60 in the sample? 2. how much cobalt-60 is left after 8.4 years? show your work. 3. what would be the y-intercept of the graph? what does it represent? 4. after how many years will the amount of cobalt-60 left be 6.25 mg? explain what happens to the cobalt-60 after 50 years? 5. discuss some “real-world” examples and uses of cobalt-60

Ineed me i stuck and i don’t want to get it wrong

The interior angles formed by the side of a hexagon have measures of them up to 720° what is the measure of angle a