G2 phase of the cell cycle is the period between DNA synthesis (S phase) and mitosis (M phase). It is a crucial phase where the cell prepares for division by ensuring that all the necessary components are synthesized and organized properly.

During G2 phase in animal cells, several important processes occur, including the synthesis of proteins. This is the correct answer to the given question. Let's explore this further:

1. Synthesis of Proteins:
During G2 phase, the cell undergoes active protein synthesis. Proteins are important macromolecules that perform various functions in the cell. They are involved in cell signaling, metabolism, structure, and many other cellular processes. The synthesis of proteins during G2 phase ensures that the cell has enough resources and machinery to carry out essential functions during division.

2. DNA Replication:
DNA synthesis or replication occurs during the S phase of the cell cycle, which precedes the G2 phase. In G2 phase, the replicated DNA is checked for errors and repaired if necessary. The cell also ensures that the replication process has been completed accurately before proceeding to the next phase. Therefore, DNA synthesis does not occur during G2 phase.

3. Formation of Spindle Fibers:
The formation of spindle fibers, which are essential for proper chromosome segregation during cell division, occurs during the prophase of mitosis (M phase). The spindle fibers are responsible for the movement of chromosomes to opposite poles of the dividing cell. Hence, spindle fiber formation does not occur during G2 phase.

4. Formation of Middle Lamellae:
Middle lamellae are structures found between plant cells and not animal cells. They are composed of pectin and serve as cementing material, holding adjacent plant cells together. Therefore, the formation of middle lamellae does not occur during G2 phase in animal cells.

In conclusion, during G2 phase in animal cells, proteins are synthesized to ensure the cell has the necessary resources and machinery for division. Other processes like DNA synthesis, formation of spindle fibers, and middle lamellae formation do not occur during this phase.