<span>One of the ways that people of ancient times classified plants and animals is by use. Today, group the creatures, as they do the plants, on the premise of shared physical attributes. They put them in a progressive system of groupings, starting with the kingdom Animalia and continuing through phyla, classes, orders, families, genera and species.</span>
Answer:
B
Explanation:
Living Organisms in an ecosystem have a food chain or energy chain. This chain links all organisms within an ecosystem, therefore, answer B "By what they eat" should be the correct answer
I believe the answer to this is D.
The answer is coal we just studied it