Azoospermia is the medical condition of a man whose semen contains no sperm. It is associated with infertility, but many forms are amenable to medical treatment. In humans, azoospermia affects about 1% of the male population and may be seen in up to 20% of male infertility situations. 1 Classification 1.1 Pretesticular.
Nematocysts are the stinging cells on tentacles of a cnidarian, like a jellyfish. Since jellyfish don't have any teeth, and their body consists of gelatin, it's hard to captur â¦ e prey.Nematocysts help jellyfish with feeding by stinging the prey in an attempt at trying to immobilizing the prey.hat is a Cnidarian? cnidarians, such as jelly fish, sea anemones, hydra, and corals, have tentacles surrounding their mouth. they are a hollow-bodied animal with two celled layers that are organ â¦ ized into tissues. the inner layer forms a digestive cavity where food is broken down.
There are about 10,000 species found in this phylum. The key characteristic features of cnidarians include radial symmetry, acoelomate body with tissues, lack of organs, and the simple digestive sac that opens through a mouth, which is surrounded by tentacles armed with nematocysts.All cnidarians are carnivores and have very simple body structures adapted as predators.he key characteristic features of cnidarians include radial symmetry, acoelomate body with tissues, lack of organs, and the simple digestive sac that opens through a mouth, which is surrounded by tentacles armed with nematocysts.