Some molecules are so small that they move between other molecules in what?

Solid atoms are very attracted to each other. They don't move past one another. The molecule are attracted to each other, however they move past one another.

Explanation:

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.