Answer:
The correct option is : a. serous fluid in the pericardial cavity
Explanation:
The heart is enclosed in a sac containing the heart, known as the pericardium. The pericardium has two layers- fibrous and serous layer.
The serous layer of the pericardium produces and secretes the pericardial fluid into the pericardial cavity.
The pericardial fluid is a lubricating serous fluid present in the pericardial cavity. It reduces the friction caused between the pericardial membranes by lubricating the epicardial surface.
Answer:
It keeps the information organized, and easy to comprehend.
Explanation: it helps us categorize organisms so we can more easily communicate biological information. It is also a way to help scientists understand and organize the diversity of life on our planet.
