Why does coelenterata are regarded as more developed species than porifera

Phylum Coelenterata and phylum Porifera are classified under animal kingdom found in aquatic environments.

Coelenterata include radially symmetrical aquatic animals and phylum Porifera contain sponges.

Coelenterata are developed species than porifera as porifera are cellular level organization and Coelenterata developed into tissue level of organisation. Porifera have pores in there body for different functions and coelenterata develop into only one opening in the body.

Porifera also do not have organs or nerve cells and coelenterata  develop themselves with simple organs and nervous system.

Hence, coelenterata have more developed body system than porifera.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds