The primary purpose of which human organ system is to produce hormones that regulate body functions

Plzz hurry im being timed during times of vigorous physical activity, muscles require a constant supply of oxygen. how does the body respond to these needs? a. breathing rate and heart rate both decrease. b. breathing rate and heart rate both increase. c. heart rate decreases, but breathing rate remains stable. d. breathing rate increases, but heart rate remains stable.

Exit what always affects measurement error in an experiment? a. investigator bias b. variability in nature c. instrument precision d. misreading the instrument

Which must be kept in mind when determining if an explanation is correct? check all that apply. which must be kept in mind when determining if an explanation is correct? check all that apply.