Question

what type of habitat are hexactinellid sponges commonly found in?
shallow coastal shore waters
deep - sea environments
freshwater lakes

Explanation:

Hexactinellid sponges, also known as glass sponges, have a skeletal structure made of silica spicules. Their delicate and intricate silica framework is better suited to the stable and low - disturbance conditions of deep - sea environments. Shallow coastal shore waters are subject to more wave action, temperature fluctuations, and sediment movement which could damage their fragile structure. Freshwater lakes have different chemical compositions (e.g., lower salinity) compared to the marine environment that these sponges are adapted to.

Answer:

deep - sea environments