Predators & defenses : Many different types of animals prey on adult sea urchins, including birds, sea otters, fishes, crabs, lobsters, octopuses, and sea stars. Eggs and larvae of sea urchins are eaten by many types of carnivorous zooplankters and by suspension-feeding invertebrates including hydroids, sea anemones, and mussels, just to name a few.
IPv4 (Internet Protocol Version 4) is the fourth revision of the Internet Protocol (IP) used to to identify devices on a network through an addressing system. The Internet Protocol is designed for use in interconnected systems of packet-switched computer communication networks (see RFC:791).
The Internet layer handles addressing, packaging, and routing functions. The core protocols of the Internet layer are IP, ARP, ICMP, and IGMP. The Internet Protocol (IP) is a routable protocol that handles IP addressing, routing, and the fragmentation and reassembly of packets. The Address Resolution Protocol (ARP) handles resolution of an Internet layer address to a Network Interface layer address, such as a hardware address.