Animal cells are interconnected by

The correct option is Desmosomes.

To understand why this is the correct answer, let's break down the functions of the structures listed in the options and differentiate between plant and animal cells:
1. Desmosomes: These are specialized adhesive protein complexes localized to intercellular junctions. They act like rivets or spot welds, securely fastening adjacent animal cells together. They are particularly abundant in tissues subjected to severe mechanical stress, such as cardiac muscle and skin epithelium, helping to maintain structural integrity under tension.
2. Plasmodesmata: These are microscopic channels that traverse the cell walls of plant cells and some algal cells, enabling transport and communication between them. Because animal cells lack cell walls, they do not possess plasmodesmata.
3. Cell Wall: This is a structural layer surrounding some types of cells, situated outside the cell membrane. It is tough, flexible, and sometimes rigid. It is a defining feature of plant cells, fungi, and bacteria, but is entirely absent in animal cells.
4. Plasma Membrane: While the plasma membrane defines the outer boundary of every animal cell, it is the individual envelope of each cell rather than the specific junctional structure that connects neighboring cells together.

Therefore, desmosomes are the specific intercellular junctions that interconnect animal cells.