What is one of the results of aerobic decomposition in composting?

The process of aerobic decomposition in composting primarily produces solid material known as compost. During aerobic composting, microorganisms break down organic matter in the presence of oxygen, leading to the transformation of food scraps, yard waste, and other biodegradable materials into rich, nutrient-dense soil amendments. This compost is valuable for enhancing soil fertility and structure, making it an essential part of sustainable agricultural practices and landscaping.

The other choices represent byproducts or unrelated concepts. Water vapor can indeed be produced during decomposition, but it is a minor byproduct rather than the primary outcome. Heavy metals are typically contaminants that may be present in certain wastes but are not products of the composting process itself. Fossil fuels are formed through geological processes over millions of years and are unrelated to composting or aerobic decomposition. Therefore, the focus on solid material, specifically compost, aligns with the main objective of aerobic decomposition in composting.