Help.​

Birth Rate

Now, this might seem very obvious to you, but when babies are born, it results in a population change! Social scientists who study this trend have some key terms, though. First, the fertility rate in a country refers simply to the number of children born. This is different from the fecundity rate, which is the number of children who could be born in a given society. In other words, fecundity is the biological capacity of humans to produce children.

Death Rate

Just as when babies are born, when members of a society die it changes the population. This might be a bit morbid to think about, but scientists refer to this as the mortality rate, which is simply the number of deaths that occur in a society. This is usually calculated by looking at the number of deaths per 1,000 individuals. In the United States, for example, the death rate is 8/1000 people. Just like birth rate, the death rate in a country depends on things such as availability of quality medical care, disease, war, or famine.

Migration Rate

One important factor that accounts for a change in population is migration. At the broadest level, migration refers to movement; it's the flow or circulation of people in societies. There are two kinds of migration: emigration and immigration. Emigration means to leave one's own country for another. Immigration means to enter into a country other than one's own.

so we know the answer cannot be c because no insect or animal starts as an adult

the answer is a. a swimming larvae

because since they are sea animals they automatticaly have to know how to swim they cannot just sink to the bottom

sorry if this is the incorrect answer.

answer; /// i believe its the cochlea;