Mr. Molesky observes a group of monkeys for 24 hours to learn about their behavior. He records how long they slept, how many bananas they ate, gender, age, and the specific breed of monkey.

a) Identify the independent and dependent variables in Mr. Molesky's study.
b) Discuss the potential ethical considerations in studying monkeys in their natural habitat.
c) Analyze how sleep duration and banana consumption might be correlated in the monkey population.
d) Suggest additional variables that Mr. Molesky could consider for a more comprehensive study.