Why is a high-dose flu shot available for people 65 and older? As people get older, their natural immune defenses can weaken and they can get sick more easily. The high-dose flu shot contains four times more antigen (active ingredient) than a regular flu shot. This helps older people develop a better immune response, gives better protection against the flu and also helps prevent flu-related complications.
Dogfish sharks are fish; fish are vertebrates, and all vertebrates have bilateral symmetry. This means they have symmetry across one plane (known as the sagittal plane, and directly down the centre of their body), which means one side of their body approximately mirrors the other side.n the northeast Pacific Ocean estimates of the age at maturity for female spiny dogfish have ranged from 20 years and 3 feet (92cm) to 35.5 years and 3.1 feet (94cm. 2 people found this useful.
The adults are recognizable by their (usually five-point) radial symmetry, and include such well-known animals as starfish, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or stone lilies. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone.The phylum contains about 7000 living species, making it the second-largest grouping of deuterostomes (a superphylum), after the chordates (which include the vertebrates, such as birds, fishes, mammals, and reptiles).chinoderms evolved from animals with bilateral symmetry. Although adult echinoderms possess pentaradial, or five-sided, symmetry, echinoderm larvae are ciliated, free-swimming organisms that organize in bilateral symmetry which makes them look like embryonic chordates.