What sort of farming defined the first type of agriculture?

sustenance
seasonal
subsistence
supplementary

So I would say B. Seasonal

Explanation:

Wheat and barley are some of the first crops people grew. People probably started agriculture slowly by planting a few crops, but still gathered many foods from the wild. People may have started farming because the weather and soil began to change.

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.