What kingdom is composed of nongreen, eukaryotic organisms that reproduce by using spores and promote decomposition?

The kingdom that fits the description of being composed of nongreen, eukaryotic organisms that reproduce using spores and are involved in decomposition is Fungi. Fungi are distinct from other kingdoms due to their unique characteristics, such as having cell walls made of chitin, rather than cellulose as found in plants. Unlike plants, fungi do not carry out photosynthesis, which is why they are referred to as nongreen organisms.

Fungi play a crucial ecological role as decomposers, breaking down organic matter and recycling nutrients back into the ecosystem. They reproduce through various means, including the production of spores, which can be dispersed by wind, water, or animals, allowing them to colonize new environments. This process of decomposition is vital for maintaining the balance of ecosystems, as it helps to clear dead material and release nutrients for use by other living organisms.

The other choices—Bacteria, Plants, and Animalia—either do not align with the characteristics mentioned (such as being non-photosynthetic and eukaryotic) or have different reproductive mechanisms and ecological roles.