At an intercalated disc, at an intercalated disc, the cell membranes of two cardiac muscle fibers are completely separated by a synapse. two cardiac muscle cells are connected by gap junctions. t-tubules unite the membranes of the adjoining cells. the myofibrils are loosely attached to the membrane of the disc. all of the answers are correct.

The correct answer is " two cardiac muscle cells are connected by gap junctions".

Explanation:

Intercalated discs are microscopic features seen in the microscope as cardiac fibers, found between the myocardial cells of the heart. These features correspond of two cardiac muscle cells connected by gap junctions. The intercalated discs allow the interconnection of multiple cardiac cell muscles to work simultaneously as a single functional organ or syncytium.

answer; (phospholipid);

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.