Final answer:
The normal biota of the cardiovascular and lymphatic systems is lacking. These systems are designed to be sterile environments, and any microorganisms that enter can cause serious infections.
Step-by-step explanation:
The current state of knowledge of the normal biota of the cardiovascular and lymphatic systems is that these systems lack normal microbiota. The circulatory and lymphatic systems are home to many components of the host immune defenses, but they do not have a normal microbial population like other parts of the body. This is because the blood and lymph vessels are designed to be sterile environments, and any microorganisms that enter these systems can quickly spread throughout the body and cause serious infections.