Question

lo 4.1. what are the similarities between the circulatory and respiratory systems?
protection against pathogens and detection of external stimuli.
transportation of oxygen in the body. and remove waste products out of the tissues and eventually out of the body, that is, carbon dioxide.
production of hormones and detection of external stimuli.
regulation of body temperature and production of hormones.
production of hormones and protection against pathogens.

Explanation:

The circulatory system transports oxygen and nutrients throughout the body and removes waste products like carbon dioxide. The respiratory system is responsible for taking in oxygen (which then enters the circulatory system) and expelling carbon dioxide (which is brought to it by the circulatory system). So, the key similarity is the transportation of oxygen in the body and removal of carbon dioxide (a waste product) from tissues and the body.

Answer:

Transportation of oxygen in the body, and remove waste products out of the tissues and eventually out of the body, that is, Carbon dioxide.