Question

ecosystems
are the ecological level at which:
biotic and abiotic elements ______
flow of energy and chemical materials occurs
include organisms and their interactions with abiotic elements

Explanation:

To fill in the blank about ecosystems, we analyze the context:

Ecosystems are defined by the interaction (or related terms like "interact", "interact with each other", "function together") of biotic (living) and abiotic (non - living) components. This is a core concept in ecology (a subfield of Natural Science, specifically Biology or Environmental Sciences). Biotic elements (like plants, animals) and abiotic elements (like water, soil, climate) in an ecosystem do not exist in isolation; they interact. For example, plants (biotic) take in water (abiotic) and carbon dioxide (abiotic) to perform photosynthesis, and animals (biotic) depend on both biotic (prey) and abiotic (habitat) factors. So the most appropriate word to fill the blank is "interact" (or "interact with each other", "function together", etc. depending on the expected answer format, but "interact" is a concise and accurate choice).

Answer:

interact (or other appropriate interaction - related terms like "interact with each other", "function together" based on context requirements)