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 (RFC 791) is the second layer in the TCP/IP protocol stack. The main functions of the internet layer are transmitting data to and from the Network Access layer, routing data to the correct destination network and device on the destination network, and handling packet errors and fragmentation.he minimum-length of an IPv4 Datagram is 20 bytes (The minimum size of an IP header is 20 bytes and this is the case of an IPv4 header carrying no data) and the maximum is 65,535 bytes (maximum possible value for a 16 bit number is 65,535).