Which of the following are considered obvious signs of death?

Body decomposition is indeed recognized as an obvious sign of death. It signifies that the biological processes that sustain life have ceased, and the body has begun to break down due to the action of microorganisms and natural decay processes. This process is typically visible in forms such as discoloration, bloating, and the presence of insects.

The other signs listed, while also indicators of death, may not be immediately observable or can be mistaken for other conditions. For example, dependent lividity indicates the pooling of blood in the lowest parts of the body due to gravity, which takes time to develop and may not be present immediately after death. Fixed, dilated pupils can occur after death but can also be influenced by various factors including medications or environmental conditions, making them less definitive. Rigor mortis, which is the stiffening of the muscles post-mortem, also takes time to set in and can vary based on environmental factors.

In summary, body decomposition is a clear indicator of death and is characterized by observable physical changes that leave no doubt of the deceased state.