A gene is a segment of mrna

An RNA single-stranded molecule that is complementary to one of a gene's DNA strands, to be precise.

Explanation:

DNA sequences or segments code for proteins or molecules with defined functions, called genes.

the reason the two sea urchins don't compete with each other for food, resources, etc. is because the urchins have adapted to the environment but they have also adapted to each other. this is most likely because the genes of the sea urchins.

for the points