The cutoff between normal and low birth weight is about pounds.

The answer is 5.5 pounds. Low birthweight is a duration used to describe babies who are born weighing less than 2,500 grams (5 pounds, 8 ounces). In contrast, the average newborn weighs about 8 pounds.  Babies born with low birthweight may be more likely than babies born at a normal weight to have certain health conditions later in life, including Diabetes and Heart disease.

clumped distribution, because you'de have all of the population gathered in a relatively small are.

it's the most common because it provides protection and a mate for reproduction

example: humans, seeweed, cattles, etc.