Which of the following statements regarding cnidarians is true? The digestive and circulatory compartment of cnidarians is called the gastrovascular cavity. Cnidarians have three true tissue layers. Cnidarians are herbivores and can be destructive grazers on seaweeds. The more stationary cnidarian body form, which is cylindrical with a ring of tentacles, is the medusa.

1, 3, 4, (and maybe 5, I dunno bout that one)

Explanation:

Lymphocytes identify foreign intruders and produce special proteins called antibodies. The surfaces of invading organisms have proteins called antigens. Antibodies lock onto antigens, neutralize their toxins, and flag them for destruction. Antibodies are highly specific. They fit into certain antigens like a key into a lock, but are harmless to other antigens. For example, the antibodies that fight chicken pox are useless against polio. Antibodies can take anywhere from a few days to many months to develop. Once produced, however, they continue to exist in the body. If the same antigen invades the body again, the antibodies are already there to destroy them. This is why certain diseases, like chicken pox, are only contracted once.