Organ Systems. When a group of organs work together to carry out a body function this is the what it is called.
Integumentary system. This is the external covering of our body, our skin.
Skeletal System.
Muscular System.
Nervous System.
Endocrine System.
Cardiovascular System.
Lymphatic System.
Answer:pretty sure its A the others DIRECTLY affect the digestive
Explanation:
Electrocardiography (EKG) can be measured both noninvasively with electrocardiogram (and it's the most common, totally safe and painless method), as well as invasively with implantable loop recorder (used in extraordinary circumstances).
A quantity that does not equal 0, a real nonzero number must be positive or negative and a complex nonzero can have real or imaginary parts