Serous fluid in the pericardial cavity serous fluid in the pericardial cavity is a remnant of embryonic development increases friction between the beating heart and the outer wall of the pericardial sac is a slippery fluid secreted by the fibrous pericardium is secreted by the heart itself is secreted by the epithelial cells of both layers of the serous pericardium

The correct answer will be option-is secreted by the epithelial cells of both layers of the serous pericardium

Explanation:

Serous fluid is a fluid which resembles the serum of the blood in its color which is pale yellow to transparent.

The serous fluid is present in the cavities of the body organs like in heart, the fluid is present in the pericardial cavity.

The serous fluid lubricates the wall of the heart and is produced by the serous pericardial membranes. The secreted fluid gets collected between the pericardial cavity which helps slide the smooth movement of the serous layer against each other.

Thus, secreted by the epithelial cells of both layers of the serous pericardium is the correct answer.

1: most common garden plants prefer loam — soils with a balance of different-sized mineral particles (approximately 40% sand, 40% silt, and 20% clay) with ample organic matter and pore space. however, some plants grow better in sandy soils, while others are well-adapted to clay soils.

2: available water capacity is the maximum amount of plant available water a soil can provide. it is an indicator of a soil's ability to retain water and make it sufficiently available for plant use. available water capacity is the water held in soil between its field capacity and permanent wilting point.

3: it is the same for all living things (plants and animals). it also includes very tiny organisms that our eyes cannot see. they are known as microorganisms, and include viruses, bacteria and fungi.