Independent & Dependent Variables

I am a scientist conducting an experiment. I change a variable in the experiment and then measure what happens because of the variable that I change. Which of the following is the thing that I measure in the experiment?

I am a scientist conducting an experiment. Which of the following is the thing that I make sure stays the same in every trial of my experiment?

A bug repellent was sprayed on one arm. On the other arm, the bug repellent was not sprayed. After 2 hours, the number of bug bites are recorded. What is the independent variable?

A bug repellent was sprayed on one arm. On the other arm, the bug repellent was not sprayed. After 2 hours, the number of bug bites are recorded. What is the dependent variable?

Javier and his twin sister both have the same science exam. Javier sleeps for 9 hours the night before the exam and his sister sleeps for 6 hours. After they take the test, they both compare their test grades. What is the independent variable?

Javier and his twin sister both have the same science exam. Javier sleeps for 9 hours the night before the exam and his sister sleeps for 6 hours. After they take the test, they both compare their test grades. What is the dependent variable?

Group A decides to exercise for a month. Group B decides not to exercise during the same month. Afterwards, they measure the amount of weight that each group lost. what is the independent variable?

Group A decides to exercise for a month. Group B decides not to exercise during the same month. Afterwards, they measure the amount of weight that each group lost. what is the dependent variable?

One plant is given sunlight every day. Another plant of the same type is not given any sunlight. After 3 weeks, the height of each plant is measured. What is the independent variable?