The skeletal system functions in a. blood cell production. b. mineral storage. c. movement. d. All of these are correct

The skeletal system has several important functions in the body, including supporting the body's structure, enabling movement, protecting organs, storing minerals and lipids, and producing blood cells.

Option a: Blood cell production - This is correct, as the skeletal system is responsible for producing blood cells in the bone marrow, found within certain bones. Option b: Mineral storage - This is also correct. Bones store minerals such as calcium and phosphorus, which are essential for various body functions. Option c: Movement - This is correct as well. The skeletal system, along with the muscular system, allows for movement by providing a supportive structure and points of attachment for muscles. Option d: All of these are correct - Based on the evaluation of options a, b, and c, we can conclude that this option is correct. Each of the other options is a valid function of the skeletal system, making this the most accurate answer.

Based on the analysis of each option, the best answer is option d: All of these are correct. All options (a, b, and c) describe important and accurate functions of the skeletal system, making option d the correct answer to this exercise.