This document discusses the challenges and advancements in wireless sensor networks (WSNs), focusing on the TEEN (Threshold-sensitive Energy Efficient Sensor Network Protocol) which employs hierarchical clustering for efficient energy use. It identifies the protocol's limitation in communication when thresholds are not met, resulting in undetected dead nodes, and proposes a solution whereby nodes notify the base station of their energy levels throughout their operation. The conclusion emphasizes the ongoing research into enhancing energy efficiency and network lifetime in WSNs.