Final answer:
RNA stability can be decreased by factors such as the removal of protective caps, and interactions with RNA-binding proteins and microRNAs, leading to a shortened lifespan and reduced protein synthesis.
Step-by-step explanation:
The cause of RNA having decreased stability, which shortens its lifespan, can be attributed to several factors. RNA stability is essential for determining how long RNA molecules stay in the cytoplasm and thus affects how much protein synthesis can occur. Factors affecting this stability include the removal of protective caps like the 5' cap and the poly-A tail, interaction with RNA-binding proteins (RBPs) and microRNAs (miRNAs), and environmental conditions. RBPs and miRNAs may either stabilize or destabilize RNA by binding to the untranslated regions (UTRs) and influencing whether RNA is degraded or translated into proteins. Degraded RNA cannot be translated, thereby decreasing its functional presence and its contribution to protein synthesis.