Answer:
The correct answer is -
Euglena - single-cell organism
Onion bulb - organ
Blood - tissue (connective tissue)
Explanation:
The level of organization of an organ, or organism could be cellular level, tissue level, the organ level, organ system, or a complete organism. These levels are formed by assembling the lower level of the organization.
Euglena is a single-cell eukaryotic organism found in freshwater. These organisms have a very simple level of an organism which is cellular level. The onion bulb is the organ of the onion plant composed of shortened, compressed, underground stems (tissue) that are an organ-level organization.
The blood is considered as connective tissue due to the blood cells present in the matrix called plasm thus, blood is connective tissue.
