Final answer:
The infection caused by a needle stick enters through the skin, which serves as a portal of entry, allowing the pathogen to enter the bloodstream through the parenteral route.
The correct otpion is 1.
Step-by-step explanation:
An infection caused by a needle stick enters through which portal of entry? The correct answer is 1) Skin. Since the circulatory system is a closed system and is normally sterile, pathogens require a breach in the skin to gain entry.
A needle stick provides such a breach, allowing microorganisms to bypass the skin's defenses and gain direct access to the bloodstream. This is known as the parenteral route of infection, which is one of the various means by which pathogens can enter the body, including through mucous membranes and other breaks in the skin.
The correct otpion is 1.