Please answer the following choices

Question 1

You plan to determine whether an acute, exhaustive treadmill exercise intervention (2 hours running at increasing speeds) alters immune responses to SARS-CoV-2 infection in hamsters, and whether this differs by sex. You purchase 20 male and 20 female hamsters. 10 of each are assigned to run on a treadmill for 2 hours, while the other 10 of each remain sedentary. You then infect the hamsters with SARS-CoV-2 and measure the immune response. Sex is an example of a(n) _________________.

Independent variable

Dependent variable

Question 2

You plan to determine whether a vegan diet, a vegetarian diet, or an omnivorous diet causes changes in body weight in males and females in younger, middle aged, and older adults. You recruit 120 male subjects and 120 female subjects in each age group and assign 40 each to one of the three diet conditions. You measure body weight before and after a 6 month diet intervention to determine if there are sex- and/or age-dependent differences in responses to the diets. Sex is an example of a(n) __________.

Independent variable

Dependent variable

Question 3

You plan to determine whether a dietary supplement improves hydration status after either water or sports drink ingestion in males and females when compared to placebo. You recruit 30 males and 30 females to your study. Over 4 weekly visits, they receive one of each treatment combination: supplement + water, supplement + sports drink, placebo + water, placebo + sports drink. You measure hydration status by urine specific gravity over 6 hours. Sex is an example of a(n) _____________.

Independent variable

Dependent variable

Question 4

You plan to determine if exercise training protects against heart disease. You divide a group of 1000 subjects into exercised or sedentary groups, and the exercised group receives 2 years of a directed training intervention. You follow these individuals for heart attacks during the following 5 years. The intervention (exercised or sedentary) is an example of a(n) ________________.

Independent variable

Dependent variable

Question 5

You plan to study how individuals in different age groups respond to one of three doses of a therapeutic drug. You treat these groups with the drug and measure the resulting rate of disease. The disease rate is an example of a(n) ________________.

Independent variable

Dependent variable