Which of the following best describes the difference between the departments of defense and homeland security? a. the department of defense is mainly responsible for protecting us borders, while the department of homeland security manages military operations abroad. b. the department of homeland security assists in counterterrorism measures, while the department of defense secures us borders from illegal immigration. c. the department of defense manages the military overseas, while the department of homeland security manages and trains the military on us soil. d. the department of defense manages military operations and training, while the department of homeland security educates and assists americans in preventing terrorist attacks on us soil.