Final answer:
Tight junctions are the type of junction that prevent the movement of chemicals between two adjacent animal cells, creating a watertight seal.
Step-by-step explanation:
The type of junctions that prevent the movement of chemicals between two adjacent animal cells are known as tight junctions. These junctions form a watertight seal between cells, preventing substances in the extracellular matrix from slipping between the cells and ensuring that materials pass through the cells themselves rather than between them. This is in contrast to gap junctions, which actually act as channels allowing for the transport of ions, nutrients, and other small molecules between animal cells. Desmosomes act like spot welds providing mechanical stability, and plasmodesmata are channels found between plant cells, not animal cells.