Which types of cell junctions are needed in a mucosal membrane, such as the digestive tract, to keep the digestive enzymes, juices, and bacteria from leaking out?

The correct answer is tight junctions.  

Tight junctions are found mainly in the epithelial cells like an intestinal brush border. Water and other fluids must be inhibited from crossing or sipping between the neighboring cells, so that the fluids do not slowly goes across the intestinal lining.  

Tight junctions seal adjacent epithelial cells in a narrow band just within their apical surface. They comprise of an alignment of claudins and other proteins. One of their essential function is to restrict the movement of ions and molecules via the space between the cells.  

sand 60

clay 10

silt 30

sandy loam should be dominated by the sand. as the amount of sand increased, the amount of slit needed to anchor the plants' roots to the sand will also be increased. even though the amount is very little, 10% part of clay is still necessary for proper oxidation.

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex