A. Organ level
A.
B. Tissue level
B.
C. Cellular level
C.
D. Organ system level
D.
Correct Answer: C
সঠিক উত্তর: C
Explanation
ব্যাখ্যা
The phylum Porifera (sponges) represents the most primitive multicellular animals. Their cells are loosely aggregated and do not form true tissues or organs. Hence, they exhibit a cellular level of organisation.