Final answer:
The statement is false; not all human blood contains bloodborne pathogens. These pathogens can cause disease primarily in individuals with weakened immune systems, and are introduced to the bloodstream in various ways.
Step-by-step explanation:
The statement that bloodborne pathogens are present in all human blood and will cause disease in people who have weak immune systems is false. Not all blood carries bloodborne pathogens; however, when these pathogens are present, they can indeed cause disease, especially in individuals with compromised immune systems. Pathogens are introduced to the bloodstream through various means, including contaminated catheters, dental procedures, piercings, or wounds. An individual's susceptibility to infections also depends on their immune system function, which can be weakened by conditions such as HIV, resulting in fewer white blood cells and a reduced ability to fight off pathogens.