Research on Connectivity Protocols in Wireless Sensor Networks (WSNs) focuses on maintaining seamless communication among sensor nodes despite challenges like node failures, mobility, and energy depletion. These protocols are designed to ensure that the network remains connected and resilient by managing node placement, adjusting transmission power, and utilizing redundant paths for fault tolerance. Recent studies emphasize energy-efficient and adaptive connectivity mechanisms that dynamically adjust topology while balancing node energy consumption to prolong network lifetime. Some approaches integrate coverage and connectivity optimization, ensuring that sensing and communication goals are met simultaneously. Additionally, machine learning and bio-inspired algorithms have been explored to predict link failures and reconfigure connections in real time. Overall, connectivity protocols play a crucial role in ensuring reliable data transmission, scalability, and robustness in modern WSN deployments.