Severe cases can even lead to death. Best way to protect yourself from getting the flu? Get an annual flu shot. When is flu season? The flu season occurs in the fall and winter, but the virus can stay active year-round. Is the flu virus contagious? Yes, it is very contagious. You can have the flu for 1 to 4 days before you start feeling sick.
Some mollusks have bilateral symmetry. Mollusks include gastropods such as snails, bivalves such as oysters, and cephalopods such as squid. Some bivalves have bilateral symmetry. Some mollusks have bilateral symmetry. Mollusks include gastropods such as snails, bivalves such as oysters, and cephalopods such as squid.
Body Structure and Symmetry. Mollusks have a very distinct body structure of a significant cavity used for breathing and excretion. Mollusks have a body without a cavity, has more than two layers of cell layers, tissues and organs. Mollusks are soft bodied animals with three main regions: head, visceral mass, and foot. The head of the mollusk contains the sense organs such as the brain. It has a pair of eyes, a mouth, sensory and nervous structures.