Range Minimu Query: Given an array A[1,n] of n ordered objects (such as numbers), a Range Minimum Query (or RMQ) from i to j asks for the position of a minimum element in the sub-array A[i,j]. RMQs can be used to solve the lowest common ancestor problem.
The reasons that we do not eat or recommend shellfish are very similar. Shellfish are bottom feeders and feed on parasites and dead skin, many times from dead animals. They do not have appropriate digestive and filter systems to purify toxins and parasites from their body and flesh.
There are two kinds of shellfish: crustacea (such as shrimp, crab and lobster) and mollusks (such as clams, mussels, oysters and scallops). Reactions to crustacean shellfish tend to be particularly severe. If you are allergic to one group of shellfish, you might be able to eat some varieties from the other group.