Eventually, I replaced it with a full-size tire, but I've always wondered why manufacturers say you shouldn't use the spare for longer than necessary. Since the spare tire is used so infrequently, carmakers have switched to narrow, compact spares to save space and weight. Of course, a spare tire is a lifesaver when regular tires go pop, but leaving the temporary tire on for longer than the manufacturer recommends invites a host of problems. First, a temporary spare isn't as durable as a normal tire.
Cells have become specialized and form true tissues and cnidarians are the first group to have B nerve cells organized into a nerve net B sense organs (statocysts and ocelli) B extracellular digestion Cnidarian Body Plan The diploblastic cnidarians are radially or biradially symmetrical with oral and aboral ends.
Cnidaria is a phylum or scientific classification involving about 9000 species of animals that mostly can be found on water. Animals that belong to this scientific phylum or class are called âcnidariansâ. Cnidarians have distinct cells called âcnidocytesâ which are mainly used for catching prey.Most members of the Cnidaria phylum have jelly-like bodies like the common jellyfish known to people.Other animals belonging to this group include corals, sea pens, hydras, and sea anemones.For some people, some members of the Cnidaria phylum may seem to look more like plants but are actually animals that have similar structures to other âcommonâ animals like fishes, birds, reptiles, and mammals.he last group of Cnidarians is called Hydrozoa and this group includes a very diverse collection of sea creatures and forms. Most members of the Cnidaria group eat plankton and other animals to survive.