Answer:
They are all living, they are multicellular organisms, they are all members of a kingdom, have DNA, etc.
Explanation:
A polymer composed of many glucose units
They are called archaea, or "ancient" because they were the first bacteria in their lineage. Also they are in the the kingdom Archae, which is considered one of the main kingdoms of life.
Producers: Create food/Product
Consumers: Eat the food/Use the product
Decomposers: They can decompose after death. They could be Producers or Consumers while they are living, but ya' know... they are dead now, so....
I hope I helped.